added code format/style test and fixed up code

I converted all instances of `'''` to `"""` because PEP267 uses the double-quotes.

I also moved the param types into the `:param <type> <name>:` format.

Fix PEP8 things in a few places.
Another alternative is that we could put the implementation of `ament_pep8`, `ament_pyflakes`, and `ament_copyright` into either `ament_package` or `osrf_pycommon`. The way I see it, only `osrf_pycommon`, `ament_package` and `ament_tools` would all benefit from these checks. The down side is that the settings for these linters are not contained within the actual `ament_*` packages, but instead they are simply the xunit/cmake integration.