Do not move cursor with emit or capture

[snoe]

PR for half of #10.

This change maintains cursor position if a bracket happens to move the current character.

It also maintains cursor position from undos after capture or emit except for something I was unable to solve: capture-head on a top level form and undoing will move the cursor to the head of the list.

Cheers

[elmehalawi]

Is there any chance of this being merged? This is a huge improvement to the default behavior.