added support for notification sounds with Pushover API
changed "sound" option name to the more specific "message_sound" name
adding documentation for Pushover's sound support in README.md
tweaked README for a more exclipit description of the loadmod function
updated wording for footnote
tweaked format
added more formatting changes
more formatting tweaks
reordered notification settings for default options so that user's can
set message_sound and message_uri on module load
re-ordered notifications settings doc
reorganized configuration section of docs and default options of module.
docs and default options should now be properly aligned.
Removed section about loadmodule defaults
Merge pull request #32 from mingtang/master

Pushover Sound Support