Clean up .gitignore

Remove all the ignores from `.gitignore`. The default boilerplate
doesn't generate any project-specific files that need to be ignored. All
OS and Editor-generated files should be globally ignored rather than
polluting the local project ignores.

Further information on using git ignore's appropriately can be found in
the miscellaneous part of the bundled docs.

.gitignore

@@ -1,52 +1,2 @@
-# Read about how to use .gitignore: http://h5bp.com/ae
-
-# Numerous always-ignore extensions
-*.diff
-*.err
-*.orig
-*.log
-*.rej
-*.swo
-*.swp
-*.vi
-*~
-*.sass-cache
-
-# OS or Editor folders
-.DS_Store
-._*
-Thumbs.db
-.cache
-.project
-.settings
-.tmproj
-nbproject
-*.sublime-project
-*.sublime-workspace
-
-# Dreamweaver added files
-_notes
-dwsync.xml
-
-# Komodo
-*.komodoproject
-.komodotools
-
-# Espresso
-*.esproj
-*.espressostorage
-
-# Rubinius
-*.rbc
-
-# Folders to ignore
-.hg
-.svn
-.CVS
-intermediate
-publish
-.idea
-
-# build script local files
-build/buildinfo.properties
-build/config/buildinfo.properties
+# Include your project-specific ignores in this file
+# Read about how to use .gitignore: https://help.github.com/articles/ignoring-files