Update README.md

Added in simple usage instructions.
Update README.md

Added in the appropriate links.
Store the current room in the sessionStore

If there is no room specified in the session store then look for one in
the URL query string. If there is not one in the query string then
create a new room.
Share the query string between presentations

Because the default presentation uses the query string to show differnt
transitions and themes this checks for a change in the query string and
communcates it to the other presentations to ensure syncronization.
Temporary hack to display the sharing URL.

Hook the Ctrl+g keypress to pop up a dialog box to display the sharing
URL for the presentation.
Merge branch 'master' of github.com:gordienoye/go-reveal
Update readme to reflect new method of sharing the presentation URL.
create share button
share url now in text input
Merge pull request #1 from gordienoye/share-style

create share button
Merge branch 'master' into gh-pages
Added in default presentation from Reveal.js