Fix a couple of critical bugs related to lite-xl startup and to binary file opening.

Implement subpixel text positioning to improve text layout at small size. Please not that some spacing inaccuracies still remains when using FiraSans.

Implement close button for tabs. An option to disable the tabs button will be implemented in the next release.

Make the command view list of suggestion scrollable to see all the items.

Improve update/resize behavior of treeview and toolbar.