Navigator: set loiter WP correctly
Merge pull request #666 from PX4/fix_loiter

Navigator: set loiter WP correctly
Added comments for L1 control parameters
Missing descriptions added for L1 control parameters
Rename parser.py to srcparser.py to prevent naming conflicts with built-in Python parser library.
Fixes for Python 3: Use sorted() with key parameter instead of deprecated (and removed) cmp() function.
Fixes for Python 3 and refactoring: Merge generic Output class into specialized output classes as some need to write files in binary mode.
Merge branch 'beta' of https://github.com/Highlander-UA/Firmware into param_docs
Fixed Doxygen comments and added parameter documentation group.