remove smart_edit

[jtorjo]

when expression is a bit more complex, this just slows down the app - better to just implement a simple caret + allow selection - i mean, pretty much i've done just that.

the rich edit just seems to slow thing down

need to care about

• multiple lines (how do i tackle that? - maybe alt-arrowdown/arrowup?)
• multiple fonts within the text
• when i'm scrolled (for starters, perhaps don't allow it at all - and just act as pagedn/pageup when at end/start of line?)

TOTHNK how i compute the character positions/widths?? (no need for caching)