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.

This was done via:
1) Pulling out a shared resource dictionary for error reporting functionality and other common functionality (can be used later for other WPF related dialogs)
2) Using FSharp.ViewModule to dramatically simplify the RenameDialogModel, while also providing better user level feedback
3) Cleanup to remove "code behind" and event-based handling via FsXaml provided attached properties and converters
A stylistic suggestion: we don't need `with get()` for all getters here.