Updated to docopt 0.6.16
Fix crash when adding a character at end of line

After using CTRL + E to go to the end of the line, inserting a character currently crashes iota.  This commit fixes that by delegating to `move_right`, which correctly handles the boundary condition.
Merge pull request #55 from pythonesque/patch-1

Fix crash when adding a character at end of line
Fix deletion at end of line.

Currently, after a CTRL + E, deletion with backspace fails at the end of a line.  This commit fixes that.
Adding undo and redo.

This involves adding transactional semantics to all commands that modify
data.  This is explicitly *not* optimized right now, but is instead as
simple as possible.  If it proves damaging in the immediate term, we can
easily bound the size of the undo/redo stack.
Fix arguments to rustc & cargo
Merge pull request #57 from pythonesque/patch-2

Fix deletion at end of line.
Update to latest docopt
Added note on Rust integration
Fix note formatting
Updated stdin example
Remove old usage piece
Merge pull request #59 from pythonesque/undo

Adding undo and redo.
Update key bindings
Reinstating Ctrl-x variants of save and quit.
Merge pull request #60 from pythonesque/fix_readme

Update key bindings
Un-reversing undo and redo.
Merge pull request #61 from pythonesque/fix_readme

Un-reversing undo and redo.
Fixing undo/redo across pages.

This just replicates the functionality already used elsewhere to perform
scrolling.  At some point it should be refactored to be shared.
Merge pull request #63 from pythonesque/fix_undo

Fixing undo/redo across pages.