Fixed bug that left a '-1' tabindex on a select after destroying selectize

Selectize sets a '-1' tabindex on the original select element when
initialized. When the select element did not originally have a tabindex
set, Selectize would not properly remove the '-1' tabindex when
destroying itself.
Changed tabs-as-spaces to just tabs
Reverted changes to files in the dist folder

Because I just read the notes for contribution in the README.
Changed tabs-as-spaces to just tabs
Defensive check around e.preventDefault in onFocus
Don't scroll up if unnecessary

Scroll down in dropdown then press UP.
Before fix : dropdown scrolls up even if unnecessary, e.g. the new active option is entirely visible in the dropdown.
After : dropdown scrolls up only if the target option is out of the visible part of the dropdown.
Consistency this-self
Merge pull request #179 from djspig/issue/178/Error-when-disabled-selectize-is-initialized

Defensive check around e.preventDefault in onFocus
Merge pull request #171 from FMXpress/master

Fixed bug that left a '-1' tabindex on a select after destroying selectize
Merge pull request #183 from dosource/master

Don't scroll up the dropdown if unnecessary
Fix for IE :required issue (#180).
Fixes bug affecting values that match "$\d+" (#172).