Type error fix for empty string

When input value is a empty string of spaces, date validator returns
null, and `formatted = date.format(format);` gives a type error. This
commits returns false on such cases.

Fixed indent.
Add possibility to custom sort function

This opens to the possibility of passing a custom user function to sort
the order of a specific column.
update credit card regex
Merge pull request #1272 from SergioCrisostomo/card-regex-update

update credit card regex
Fixed Scroller class issue when passing 'window' as element.
docs update
Merge pull request #1269 from SergioCrisostomo/scroller-fix

Scroller fix
Merge pull request #1270 from SergioCrisostomo/fix-1030

Type error fix for empty string on 'validate-date'
docs update with new sort parameter
call it sort instead
Merge pull request #1271 from SergioCrisostomo/HTMLTableSort-additions

custom sort function
use new packager version
Merge pull request #1275 from SergioCrisostomo/update-packager-version

use new packager version
remove old packager
remove Core submodule and old Specs-Runner
Merge pull request #1277 from SergioCrisostomo/remove-old-packager

remove old packager, old Runner and Core submodule
add onLoad callback for cross-origin CSS assets
Merge pull request #1278 from SergioCrisostomo/cssAssets

add onLoad callback for cross-origin CSS assets
Fix sort regex to respect sci-notated float number

Failing spec: http://jsfiddle.net/LaLsd/
Fix by @enigmamf
Fix scroll miss-placement while dragging

When dragging and scrolling happen at same time, the dragged element
does not follow the scroll and gets "left behind". This commit/PR fixes
that. The old behavior is still optional.