Hook into property values.

Makes setting and getting a form field's value property with `jQuery#prop`
behave the same as `jQuery#val`.

Libraries like bootstrap-datepicker use `jQuery#prop`.
Added bower.json
Added some notes about bower to the readme
Merge pull request #95 from thebestday/prop-hooks

Hook into property values through `$.propHooks`
Merge pull request #143 from benschwarz/bower

Add `bower.json`
Remove GPL license

MIT is GPL-compatible anyway.
Add unit tests
Delete unused variable `$origInput`

Closes #131.
Add `.prop('placeholder')` tests (failing for now)

These tests describe the functionality that #145 is asking for.

Closes #147.
Merge pull request #1 from mathiasbynens/master

merge from mathiasbynens