Use verb pattern

This pull request is a WIP.

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This is a major refactor for the verb's to use the generalized "verb pattern" now in osrf_pycommon:

https://github.com/osrf/osrf_pycommon/pull/6

This pull request also refactors `build` and `build_pkg` to use the concept of BuildType and BuildActions to define build workflows for different `build_type`'s.