Fix bug to support application/xhtml+xml

I tracked down this bug as part of debugging this issue: https://github.com/ankit/stylebot/issues/156

xhtml requires that all tags are properly closed
Updated measureString to return 0 for an empty string.
In autoGrow, track the input's current width in a closure rather than
using jQuery .width() to see if the width needs updating.
don't preload results in setup() when preload option is set to focus
Select option with TAB key

A client asked me they want to able to select an option by pressing tab. I thought it would be nice if Selectize has this feature by default.
Allow CTRL N/P to control down and up
Fixed compilation problems introduced by Bootstrap (now requires less >1.4). 
Mentioned in #282.
Merge remote-tracking branch 'refs/remotes/caseywebdev/ctrl-n-p'
don't trigger dropdown when creating item on blur

When using a multiple select with the createOnBlur option enabled, the
options list remains open when the control is blurred and a new item
is entered into the input. This patch adds a toggle to the createItem
method to prevent refreshOptions triggering a call to open()
remove_button: fix event handler when label contains html
Merge pull request #258 from code-guru/patch-1

Select option with TAB key
Merge pull request #267 from Deraen/feature/document-createOnBlur

Document createOnBlur (#264)
Merge pull request #245 from lananelson/fix-preload-on-focus

don't preload results in setup() when preload option is set to focus
Merge pull request #243 from enoshixi/master

Updated measureString to return 0 for an empty string.
Merge pull request #230 from ankit/patch-2

Fix bug to support application/xhtml+xml
Manual merge of #330 from @jkimbo w/o built files.
Added testem and grunt-cli to package.json deps.
Optimization of setValue by @jeff-mccoy (#306).
Released 0.9.0.
Fix blurOnEmptyReturn.

Nothing should be selected if input value length is zero (eg. input is
empty). Instead nothing was selected if length was true (eg > 0).
Merge remote-tracking branch 'upstream/master'