Plugin SourceSFSVN : fix wrong comparison of SourceChangeset action
Plugin SourceSFSVN: Allow viewing removed files
Porting fixes from SourceWebSVN to SourceSFSVN

This follows discussion on https://github.com/dregad/source-integration/commit/deba255e873879791c339c4efb5e46cef95f2d34#commitcomment-2713308

Changesets deba255e873879791c339c4efb5e46cef95f2d34 and
c11a010d491ec7f80fd4b842dc8770098af2fc44 for SourceWebSVN apply mutatis
mutandis to SourceSFSVN.

Fixes #52