Fix bugs in cursor movement during delete

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Abort command mode on weird key

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Emulate Ctrl-C in urwid UI

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>
Move commands to their own file

Signed-off-by: Casey Dahlin <casey.dahlin@gmail.com>