Add extensive format validation, bugfixes

* Don't just assume we were given one of the valid formats.
* Also consolidate the parsing states that occur after timePeriod.
* Add subtests to make it easier to see what fails.
* Additional tests for 4-char timezone names.
* Fix araddon#117
* Fix araddon#150
* Fix araddon#157
* Fix araddon#145
* Fix araddon#108
* Fix araddon#137
* Fix araddon#130
* Fix araddon#123
* Fix araddon#109
* Fix araddon#98
* Addresses bug in araddon#100 (comment)

Adds test cases to verify the following are already fixed:
* araddon#94