Select the navbar parent in js and add a class

This will keep us from having to add extra markup for no reason. I
allowed for a jQuery object and string selector, also added a nice error
in case something else was put in there.
Remove fail-safes.

Assume users know what they’re doing.
Update read me to use new style names
Update html to contain new information
Remove useless if statement
Fix Firefox mega menu issue

Closes #46.
Update demo to account for theme-simple

It needs the strong tag in order to be designed correctly.
Position icon-caret-down and left-align simple
Remove navtacular-cover transition
Fix position of blue icon-caret-down
left-align blue
Update readme
Merge pull request #48 from stezu/master

Fixing bootstrap headache + a bunch more stuff