tkdiff Code

Merge output SaveAs browser now correctly responds to directory traversals

Repaired one bug, and two oversights affecting general usage scenarios
- Eliminated default <CR> to <NL> input conversions causing crashes/missing-hunks
- Wheel-scrolling now works when over the MAP (it targets the 'active' window)
- Cmdline outputfile naming is now cancelled if/when multi-file support is active.
Accordingly, an ellipsis (...) now dynamically appends to pertinent GUI elements
to hint pgm WILL prompt (or not) for the filename as the situation requires.

Fixed a Split/Combine corner case causing key internal data to be shifted
- hunks beyond the CDR were shifted if the amount of padding was changed
- inline tagging now uses a base/displacemnt method to avoid ANY shift

Resolving small inconsistencies in startup behavior and messages
- add/align extra failure msgs regarding insufficeint items to compare
- reduce confusion (int/ext-ernal) about when newDiffDialog appears
- simpler solution to earlier (-r103) fix (avoiding 'string cat' use)
- increase 'package requires tk' to minimum version of 8.5
- add missing 'update-display' call if startup yeilds zero diffs

Use join instead of string cat, to preserve compatibility with wish 8.5

Revise Git detection and reset multifile choice after a new diff

Reworked contrib'd "Git multi-file" feature to fit within an overall internal
redesign allowing for other sources of multiple files (dir-to-dir, other SCMs),
while also addressing its original integration missteps of existing features
it mangled (notably edit, report output, and a lack of online help info).

Repair condition chk for Split activation when only 1 hunk exists

Provide Split/Combine diff hunk feature

"tag_copy_by_TkSVN"