Add basic Copy, Cut and Paste commands (I think).

Tests needed!
Related to #22.
Related to #23.
Related to #35.
added Undo/Redo Test on initial Stack
Merge pull request #365 from snowiow/master

added Undo/Redo Test on initial Stack
frontend/qml: Good bye "Len". WIP for #303
Add Copy, Cut and Paste tests and sort the regions before iterating through them.
Use flag package, allow toggling console presence
Adjust unittest
Comply with gofmt
Merge pull request #367 from Joushou/termbox-flag

Use "flag" for command line arguments
Fix formatting.
Merge pull request #366 from erbridge/copycutpaste

Basic copy, cut and paste commands
avoid panic when theme isn't loaded closes #248
Fix some glitchy output in termbox frontend
Show file name on tabs
Handle termbox.EventResize
Merge pull request #369 from Joushou/glitchytermbox

Fix some glitchy output in termbox frontend
Merge pull request #370 from Joushou/resizesupport

Handle termbox.EventResize
Fix TestViewLoadSettings failiure
due to relative path problem
more detail on issue https://github.com/limetext/lime/pull/353/files#r17519626
backend/commands/move: Clamp cursor pos to allowed positions.

Fixes #378
frontend/termbox: Last line line number + cursor. For #376