[time.js] Various fixes for time.Time.newFromIso8601

time.Time.newFromIso8601 now properly analyzes the given string and extracts day, month and year
from it, rather than leaving this to the parser which is still unreliable for this (e.g. because
of global time.settings).
Also, an error will be thrown now in some cases where the string is not processable.
Fixed some issue with the time.Time constructor's options in the same change set.

Change-Id: Iefb2a85df04a73fe999802f672ea6f61d46fa7c3
Merge "[time.js] Various fixes for time.Time.newFromIso8601"