Fix users clicking on placeholder

fixes #2

- Remove the use of .text() to show placeholders, and instead make use of the after pseudo element and content tags in css to show a placeholder.
- Remove checking placeholder text vs current text. Now rely on existence of `inline-placeholder` class on element instead

  This has the advantage of when a user clicks the placeholder, the user can immediately type instead of having to reclick. The downside is this puts the onus of placeholder into the markup/css layer. Now placeholders are determined by a "data-inline-placeholder-text" attribute on the contenteditable element and accompanying css to make it use of it. Initial state of the class (whether it is on the element or not) is part of the view layer as well.

http://jsfiddle.net/jbran/XjP88/2/ as proof of concept.