Update for upstream version 1.5.1

1.5.1 (Nov 4, 2013)

* support bootstrap popover = auto
* validate method can change the value
* select2 tags mode fixed

1.5.0 (Oct 1, 2013)

* support of Bootstrap 3
* add twitter typeahed.js input
* update select2 to 3.4.3
* new options escape and sourceOptions

https://github.com/vitalets/x-editable/wiki/Release-notes