Simplified Rename process

Moved to latest FsXaml and FSharp.ViewModule to improve error handling
(better tooltips/validation support).  This simplifies the code around
rename significantly and improves error reporting
Work on progress and cancel support in rename
More cleanup work on Rename
Cleanup on Rename, added progress

Rename now includes progress tracking, plus reporting during
initialization phases
Fixed accidental file checkin
Updated to address rename issues

Addresses issues raised by @dungpa relating to rename.
Updated to FSharp.ViewModule 0.9.6 to leverage new progress
functionality and simplify rename
Fixed undisposed CancellationTokenSource
Merge pull request #511 from ReedCopsey/master

Simplified Rename process