Initial commit. Assert for interfaces homogenized.

There is no assert function checking types of an array, no function argument assert and there is no multi-condition assert f.i. with chaining:

this.assertBoolean(<var>, <condition>);

Where condition could be the previous assert result, where assert is not fired and postponed till all conditions have been fulfilled such as:

@param date {Date|null} Here the parameter can have two states...an actual date and null

I have not been able to test the proposed changes.