Work on the docs

Signed-off-by: Ian Bell <ian.h.bell@gmail.com>

Web/coolprop/HighLevelAPI.rst

@@ -4,7 +4,25 @@
 High-Level API
 **************
 
-For many users, all that is needed is a simple call to the ``PropsSI`` function.
+For many users, all that is needed is a simple call to the ``PropsSI`` function for pure fluids, pseudo-pure fluids and mixtures.  For humid air properties, see :ref:`Humid air properties <Humid-Air>`.  An example using ``PropsSI``:
+
+.. ipython::
+
+    # Import the PropsSI function
+    In [1]: from CoolProp.CoolProp import PropsSI
+    
+    # Saturation temperature of Water at 1 atm in K
+    In [2]: PropsSI('T','P',101325,'Q',0,'Water')
+
+More information: 
+
+* :ref:`Table of inputs to PropsSI function <parameter_table>`
+* :ref`More examples of the high-level API <Props_Sample>`
+* :cpapi:`Documentation for all high-level functions exposed <CoolPropLib.h>`
+
+All :ref:`the wrappers <wrappers>` wrap this function in the same way.
+
+For pure and pseudo-pure fluids, two state points are required to fix the state.  The equations of state are based on :math:`T` and :math:`\rho` as state variables, so :math:`T, rho` will always be the fastest inputs.  P,T will be a bit slower (3-10 times), and then comes inputs where neither :math:`T` nor :math:`\rho` are given like :math:`p,h`.  They will be much slower.  If speed is an issue, you can look into table-based interpolation methods using TTSE or bicubic interpolation. 
 
 Code
 ----
@@ -15,11 +33,10 @@ Output
 ------
 .. literalinclude:: snippets/propssi.cxx.output
 
+.. _parameter_table:
 
 .. include:: parameter_table.rst.in
 
-
-
 .. _Props_Sample:
 
 Sample Code
@@ -36,8 +53,6 @@ Sample Code
     #Import the things you need 
     In [1]: from CoolProp.CoolProp import PropsSI
     
-    In [1]: import timeit
-    
     # Specific heat (J/kg/K) of 20% ethylene glycol as a function of T
     In [2]: PropsSI('C','T',298.15,'P',101325,'INCOMP::MEG-20%')
     
@@ -50,6 +65,9 @@ Sample Code
     # Saturated vapor density of R134a at 0C
     In [2]: PropsSI('H','T',273.15,'Q',1,'R134a')
     
+    # Using properties from CoolProp to get R410A density
+    In [2]: PropsSI('D','T',300,'P',101325,'HEOS::R32[0.697615]&R125[0.302385]')
+    
     # Using properties from REFPROP to get R410A density
     In [2]: PropsSI('D','T',300,'P',101325,'REFPROP::R32[0.697615]&R125[0.302385]')
     

Web/coolprop/LowLevelAPI.rst

@@ -2,6 +2,10 @@
 Low Level API
 *************
 
+For more advanced use, it can be useful to have access to lower-level internals of the CoolProp code.  Also, this interface is strongly recommended for mixtures, where the high-level api has some serious limitations.  For simpler use, you can use the :ref:`high-level interface <high_level_api>`.
+
+At the C++ level, the code is based on the use of an :cpapi:`AbstractState` `abstract base class  <http://en.wikipedia.org/wiki/Abstract_type>`_ which defines a protocol that :ref:`the property backends <backends>` must implement.  In this way, it is very easy to extend CoolProp to connect with another completely unrelated property library, as was done for REFPROP.
+
 Code
 ----
 .. literalinclude:: snippets/AbstractState1.cxx

Web/develop/backends.rst

@@ -0,0 +1,31 @@
+.. _backends:
+
+********************
+Backends in CoolProp
+********************
+
+AbstractState
+-------------
+The :cpapi:`AbstractState` defines an interface between CoolProp and the rest of the world.  The public methods like :cpapi:`AbstractState::rhomolar` are meant to be called by other code, while the protected functions like :cpapi:`AbstractState::calc_rhomolar` are meant to be implemented by the other backends.
+
+Derived Backends
+----------------
+
+The backends in CoolProp provide the implementation of the protocol defined by the abstract base class.  There are a few primary backends:
+
+* :cpapi:`HelmholtzEOSMixtureBackend` : This backend is the backend that provides properties using the CoolProp code.
+* :cpapi:`IncompressibleBackend` : This backend provided the thermophysical properties for incompressible pure fluids, incompressible mixtures, and brines
+* :cpapi:`REFPROPMixtureBackend` : This backend provides a clean interface between CoolProp and REFPROP
+
+Example Backend
+---------------
+
+Code
+----
+.. literalinclude:: snippets/ExampleBackend.cxx
+   :language: c++
+
+Output
+------
+.. literalinclude:: snippets/ExampleBackend.cxx.output
+

Web/develop/index.rst

@@ -7,14 +7,21 @@ Information for Developers
 .. toctree::
 
   code.rst
+  backends.rst
   cmake.rst
   buildbot.rst
   documentation.rst
   
 Address Sanitizer
 -----------------
-1. Clang >3.6, build from source on linux following instructions
-2. Check out CoolProp using git:
+
+Address sanitizer is a module of the clang compiler that can help to pinpoint several memory problems, like addressing memory that is out of range.  
+
+The instructions here explain how to get address sanitizer working for CoolProp for testing purposes.
+
+1. You need Clang >3.6, build from source on linux following instructions
+
+2. Check out CoolProp using git::
 
     git clone https://github.com/CoolProp/CoolProp --recursive