Implements sequencer worker thread. Now repaints and input parsing are done in separate threads - which may help with the performance on Windows.

Possible performance improvements for Windows. Need to test.

Implements right-click menu for tabs.

Implements Alt+R to duplicate tab.

Implements Line Position Absolute sequence.

Fix issue with skipping unsupported sequences.

Fix issue with incorrectly drawing empty cells.

Implements insert/replace mode.

Fix scroll bar resize bug.

Implements a few DCS response sequences.

Performance improvements for resizing.

Fixes word select issue when selecting prev lines.

Using cursor position stack.

Cleans up code and fixes issue with clearing selection if writing to selected cells.

Mouse select working. Need to clean up code though