Paste into contenteditable

Move pasting code into its own file.
Filter tags in pasted content
Add clipboard specs
Add required attributes and element transforms
Escape text content
Make sure the global config is loaded first.

Otherwise the clipboard does not have access to the global
config since its filename is earlier in the alphabet.
Add pastedHtmlFilter to config
Update changelog
Offerings for jsHint
Update editable
Handle br elements
Handle blocks and clean whitespace
Remove content.normalizeSpaces()
Update build
Merge pull request #82 from upfrontIO/normalize-spaces

Remove content.normalizeSpaces()