Update documentation
Let option --explain show message IDs for --ignore

As requested in #7
Add #catkin_lint pragmas to parser

Currently, there is one pragma implemented:
#catkin_lint: ignore ID [ID [...]]

This pragma will ignore problems with the given IDs
for the current package, starting from the point where
the pragma is issued.

The parser is very strict and does not accept any whitespace in
"#catkin_lint:". Malformed pragmas are treated like comments and
silently ignored.

Fixes #7
New command line option --package-path

Adds additional package paths which are searched for available
packages but not linted by default.
Improve support for package format 2
Remove TODO list from README

All items from the TODO list have either been implemented or deemed
non-critical.
1.3.6
Merge version 1.3.6
Discontinue quantal updates
1.3.6-1