Added a 'lookup' formatter to the datatable-formatters module.

Includes tests
Merge branch 'dev-3.x' into dropdown-formatter

Conflicts:
	src/datatable/tests/unit/assets/datatable-body-tests.js
The lookup formatter now takes both an ordered array and
a simple object as a map
I fixed the declaration for the module so it doesn't
show as automatically rolled up into the datatable module.
Merge branch 'dev-3.x' into dropdown-formatter
Move the use of Y.soon to _notify()

This essentially reduces the number of calls to Y.soon
Change the value of |this| in callbacks

As per Promises A+ (see
https://github.com/promises-aplus/promises-spec/#the-then-method) the
value of |this| inside callbacks mut be the global object or undefined
in strict mode
Add "use strict" pragma
Add extra test for strict mode instead
Ignore the strict mode test when it is not supported

Remove superceded mention to |this|
Avoid calling Y.soon for an empty list in _notify()
Test if the test is in strict mode

Do not run the test for |this| being the global object when already in
strict mode
Fix #673: Fix missing em close tag
Fixed regression introduced in 3.10.0, with stale facade properties sticking
around in the case of "no subscribers".

Added unit tests for both the subscriber and no subscriber case.

All unit tests pass:
✔ [Total]: Passed: 10859 Failed: 0 Total: 10954 (ignored 95)

Slider functional tests pass.
Slider examples work manually.

This impacted slider's thumbMove defaultFn which was using a "source" property
added to the facade to figure out whether to set the value or not, and
commonly had no listeners (only surfaced by manual testing, which was why
it got missed - unit and functional tests all passed).
Added on subscribers fresh facade test also
Merge pull request #674 from okuryu/fix-#673

Fix #673: Fix missing em close tag
Fixing event-custom-base YArray.indexOf('subs ~ null'...) case.
Merge branch 'dev-master' into dev-3.x
Updating event build files.
Merge branch 'dev-master' into dev-3.x