Merge pull request #46 from vmax/master

Some small fixes
Implement Pre/PostInsert, Pre/PostDel, Pre/PostBackspace
Refactor simple autoindenting
Tab vs Spaces
Refactor signals, change operator() to method emit.
Work in-progress
Work in-progress
Final part of split screen feature
Clip drawing on widgets
No blinking when switch to whole screen
Fix crash bug when close window with Ctrl-W and split screens
Work in-progress
Work in-progress
Finish Syntax highlighting feature