tkdiff Code

Adjust math to attempt CENTERING Thumb of the DiffMap pseudo-scrollbar relative to the colorbars.
Sadly still imperfect (generally) due to mathematically induced vertical shift from ratio of linecount
to available pixel height, combined with an enforced minimum Thumb height.

Allow implied "null content" (eg. UNIX "/dev/null" or Windows "nul") files to Diff, despite the obvious result.

V5.6
* Added recursion ability into directory searching for the 1-FSpec case: allows trees
* Recursion (both single and dual FSpec forms) supports patterned-fname exclusions
* Repaired merge-preview window jump-scroll action when current hunk is changed.
* Handful of spelling typos, coding consolidations, and minor "Help" clarifications.

Repair typo-caused crash PLUS ineffective prior VPATH-logic fix; also clarify help-info

better recognize EFFECTIVELY empty CustomCode

Repair missing-Var crashes plus minor initialization faults

Update CHANGELOG for V5.5.1

Minor logic errors in Pref-morphing repaired for fast-track V5.5.1 release

Repair spurious typos, mangled wrap protection and new-user prefs logic faults

V5.5
* CRITICAL logic repair to 'blanks' suppression support for INLINE hilite!
* Preventive recoding fix to vague (Mac observed) race-condition bug w/combobox mis-creation.
* Repaired preference 'change' detection, resulting in a simplification and better rigor.
* Popup menu now disables "Edit" (file) when POP occurs over DiffMap (not a L/R window).
* Popup menu 'Find Nearest' when over DiffMap SCALES its search position based on POP location.
* Added status display of how many merge choices are presently targetted as pure Left or Right
* Internal: Preference evolution of older settings now tied to explicit versioning data
* Created a "Engine config" Prefs tab - allows access to other (git) Diff engines having ?better?
algorithms (perhaps for evaluation)? Also codifies what we need/expect FROM that underlying
engine and HOW it is accessed. Still permits ad-hoc specifications AND cmdline pass-thru.
- former diffcmd Pref now DERIVES from engine settings (remains for reference purposes)
- former ignoreblanks Pref (on/off) renamed and refers to multiple (indiv.) engine settings
- primary engine options (suppressions) specifically delineated AND configurable
- options shared among Diff and DiffSrch if command(s) 1st word matches, else distinct.
- Visual feedback of IMPLIED Diff execution PRIOR to invocation (user notification).
* Diff outputs NOT in "Normal" form, are now re-Evaluated for "Unified" format before giving up
* Added warning HILITE to Preference actions that result in FORCING a new Diff invocation.
* Internal: Dbg messaging CAN suspend arg-EVAL until KNOWN they are needed (lighter weight).
* Handful of spelling typos, internal naming and code consolidations, as always- updated Help.