Replacing all occurences of Spritz with Glance Bookmarklet

The bookmarklet as is in the master branch is broken. It is refering to
the old repositry within the code.

I have changed all mentions of Spritz into "glance bookmarklet" while
trying to keep coding style consistent.
I have used glanceBookmarklet etc. where camelCase is used and
glance_bookmarklet where underscore is used.

The README file still needs work.