align package build times by padding package names

Fixes #14
fix status line output when --no-deps is used

fixes #13
Merge pull request #17 from catkin/issue_13

fix status line output when --no-deps is used
Merge pull request #16 from catkin/issue_14

align package build times by padding package names
add ability to do verb aliasing with config files
added the --list-aliases command
added documentation for verb aliases
update dependencies in .travis.yml
fix recursion of verb aliases
added documentation about extending the catkin command with new verbs
print aliases sorted
sort os.listdir results when processing verb alias files
Merge pull request #18 from catkin/issue_8

Adding verb aliasing to the catkin command
Merge pull request #19 from catkin/issue_12

added documentation about extending the catkin command with new verbs
fix documentation linking
fixing up linking (again) in docs
add --list-aliases (-a) to catkin -h
improve validation of verb alias YAML config files
prevent infinite substitution of aliases

This is done by allowing only one substitution
for each alias
give more visibility to the prevention of infinite recursion for verb alias expansion