Use TextMate’s display name for untitled documents

Also remove use of rescan_project (as this is a no-op in 2.0).
Don’t force a text encoding for shell commands

This used to be required to have the clipboard shell commands work with UTF-8 but these have since been updated to default to UTF-8.
Don’t use ‘tr’ to strip CR line endings

We pass --strip-trailing-cr to the diff command so there is no need for manually stripping the CR characters.

Closes #2.