Allow for value change for Importance. Defaults to "Normal".

Acceptable values are "High", "Normal", "Low".
Updated to create importance type.
Phase one of unit test cleansing.
RSpec: rearrange builders test
Merge pull request #88 from auzroz/master

Added ability to define importance of Message.
Better support time formatting in the Builder
Merge remote-tracking branch 'upstream/master'