2.3.1 - update .d.ts file to support empty constructor, moment updates

This allows you to provide a new CronJobManager() constructor in TS also includes some moment vulnerability fixes WRT parsing RFC dates that may result in N^2 computations.

preserve additional options bugfix, helper function lexical this bugfix.

There were two helper functions added which assumed ECMA6's contextual this feature. However this is not implemented everywhere. So I reverted this back to using a call(this, arugments) style.

Also, additional options like utcOffset, timeZone and job start were not preserved when tabs where updated.

2.2.0 - startAll, deleteAll, fireOnTick

• deleteAll() - deletes all jobs in current manager
• startAll() - starts all jobs in manager

• fireOnTick()

• .d.ts file

ECMA 6 compatible, use date for crontab, and a test suite

• ECMA 6 compatible and can run on Node v8
• Added a testing suite for post install testing
• You can now use a Date object for adding and updating jobs