We will soon be adding a new SCMTool implementation to Power Pack to connect to HCL VersionVault and IBM ClearCase, supplanting the old community-driven ClearCase support. This change adds RBTools-side support for this. This is based on code delivered to us in partnership with HCL, but has had significant changes. The largest change is that instead of having a completely separate SCMClient implementation in RBTools, this is built into the same ClearCase client. Most of the code paths are the same between the two types of backends, and the major difference is that the diff output for VersionVault includes additional information in the headers (the VOB OID for each changed element, and a JSON-encoded blob to drop into the FileDiff's extra_data in order to do better post-processing on the diff display). There's still more to do for unit testing but functionality should be relatively complete at this point. Testing Done: - Posted changes from the current checkout (rbt post with no args) including new, modified, deleted, renamed, and binary files. - Posted changes that spanned multiple VOBs. - Posted a change that spanned multiple VOBs, including one that was not configured as part of the server-side repository. Saw expected warning. - Posted changes for UCM activities for both a single and multiple revisions. - Ran unit tests.