Incomplete commit, needs fixup

Starting on implementing standalone command to
generate debians for a given catkin package
Incomplete commit, needs fixup

Starting on implementing standalone command to
generate debians for a given catkin package
Major refactor of the debian generator

- Added bloom-generate command, which generates
debian files for a single package outside of a
bloom repository. Fixes #121
- Refactored rosdep resolving into the common
generator module and out of the debian specific
module
- New refactor allows the debian folder to exist
before generating debians. Any files which bloom
creates and already exist are overwritten.
Changes to files bloom creates must be done as
patches to the debian/* branches. Closes #146
Merge branch '0.4' of https://github.com/ros-infrastructure/bloom into 0.4

Conflicts:
	bloom/generators/debian/generate_cmd.py
	scripts/bloom-generate
Removing support for Fuerte.
Fixed package name bug in debian generator

Also fixed up the rosdebian generator and some
tests.
Fix up some tests
Typo [ci skip]
Option for a custom push url for release repos

Fixes #137
Fixed a bug where edited settings do not take

This specifically happens during bloom-release,
with the --new-track option
Merge pull request #137 from ros-infrastructure/issue_137

bloom should allow an alternative "push" url for the repository
Merge pull request #147 from ros-infrastructure/issue_147

running bloom with --new-track didn't change behavior
Merge pull request #148 from ros-infrastructure/0.4

0.4