Issue #523 fix (Reeds-Shepp planner handling length=0 case) (#524)

* Without equals sign, sometimes get points that are in the wrong direction - relative to the points before and after it- when change in x or change in y along path is 0

* Created test script for dubins path generator

* Made len == 0 it's own case, also changed 'l' to 'len' to appease travisCI

* More variable renaming to appease CI

* Broke == 0 into its own case in dubins planner, also Renaming files to appease CI

* Reverting some naming changes

* Turns out theres already a test for dubins.. not sure how I missed that

* Note to self: run the test cases on your own before throwing them at CI

* Added handling of length=0 case in generate_local_course()

* Missed reverting 'mode' back to 'm' in one spot

* Addressing style issues (line length)

PathPlanning/DubinsPath/dubins_path_planning.py

@@ -255,7 +255,7 @@ def generate_local_course(total_length, lengths, mode, max_curvature,
     ll = 0.0
 
     for (m, length, i) in zip(mode, lengths, range(len(mode))):
-        if length == 0:
+        if length == 0.0:
             continue
         elif length > 0.0:
             dist = step_size