Fix issue #1.  Save job properties to the parent project.

Some job properties, such as project-based matrix authorization, need to
be saved to the parent project.  This ugly commit duplicates the piece
that saves job property configuration so that it is saved to both the
parent project and the template project.
[maven-release-plugin] prepare release multi-branch-project-plugin-0.1.2
[maven-release-plugin] prepare for next development iteration
Refactor sub-project (untested)

Convert FreeStyleBranchProject into an extension of FreeStyleProject and
remove the FreeStyleBranchBuild type.  The new type allows us to define
specifications for the sub-projects while also retaining the descriptor
of the standard FreeStyleProject.

Refactored Jelly views for configuration based on above mentioned
changes.  Presence of descriptor allows for more reliance on including
views, rather than redefining each field.

Improvements are highly untested.  Configuration appears to save/load
corrrectly, but some additional fields like custom workspace probably
don't work.  Backward compatibility not verified.
abstraction wip