Changes update the register like in Vim

Fixes #17
EnterInsertMode passes register along to it's insert_command

This allows `"acw<some-text>` to yank the changed word into the "a" register
instead of the default.

Fixes #17
Merge branch 'master' into changes-update-register
All EnterInsertMode commands should expect a register kwarg

Since EnterInsertMode passes the register along to the insert_command (for
change commands), commands used as an insert_command should expect the kwarg
whether it's used or not.
cancel current action in normal mode by pressing escape
display current command in the status bar even if there is no repeat
display the currently selected register in visual mode
fix cancel behaviour in visual mode when a register is selected

escape will now always exit visual mode immediately
_and_ reset the input state
make README a reStructuredText file.
quieter headings
indent properly
<address>gg takes to <address> (<address>G alias)
remove one variable
Vim terminology nitpicking
add "gq" command
Merge branch 'master' into changes-update-register
Make ["r", "<character>"] in visual mode match Vim's behavior

Vim clears the selection (leaving the cursor its beginning) when using
r<character> from visual mode.
Reindent after ["r", "enter"] if 'auto_indent' in on (like Vim)
added zt and zb commands
Merge pull request #49 from orutherfurd/master

add "gq" command (calls wrap_text)