update the license.
wip: editing javascript is now possible.

There are few bugs with the implementation:

1. Sometimes the new buffer will have empty content.
2. We're changing the meaning of C-c C-s in all js buffers.
update the readme.
fix the bug pointed to in 36ee5208. find the delimiters of the javascript string properly.
don't change the keymap of all javascript buffers.
add a reminder to test C-j.
fix a typo.