- Change licence to "TCL".

- New version 8.6.7:
* (bug)[a2abc4] Wrong warp cursor position on 2nd display
* (bug)[fa3229] menu-38.1
* (bug)[2cf3d6] button-5.24
* (bug)[1534455,2945130] Key release events get _L vs _R right.
* (bug)[8c4216] listbox-4.1
* (bug)[eb2681] listbox-13.1
* (bug)[3126428] ttk::button react to image change
* (bug)[1082213] wrapped text don't start lines with whitespace
* (bug)[3217462] tri-state button on non-native theme
* (bug)[3588460] Fix file dialog -typevariable
* (bug)[e36963] event generate .e
* (bug)[6aea69] grid-23
* (bug)[f60c54] combobox-3
* (bug)[f32502] crash drawing many dashed objects
* (bug)[dac92f] text-2.[89]
* (bug)[7a838c] X11 ring buffer overflow
* (bug)[d4fb4e] imgPhoto-4.75
* (bug)[1403ea] Limits on text line size on Windows
* (bug)[ae32eb] textDisp fails in text custom config
* (bug)[7d967c] crash after IME restart
* (bug)[c492c9] disabled combobox arrow appearance
* (bug)[6b3644] Fix -alpha for 16-bit color PNG
* (bug)[775273] artifacts on Ubuntu 16.10+
* (bug)[28a3c3] test BTree memleaks plugged
* (bug)[db8c54] Stop freed mem access in warp pointer callback
* (bugs) Fix calculation of ttk::notebook tab widths
* (bug)[291296] notebook tab management