Rewrite timer types to use a class and not a dictionary

[FIREdog5]

Ok, using a dictionary is just gross, lets use a class instead.. you would probably be able to cut down on the fields for the timer too, by having a constructor with a default function value, so NEEDS_FUNCTION would no longer be necessary. Modifications needed to at least Utils.py and Timers.py. Maybe this new class should just be declared in the Timers.py file?

[FIREdog5]

It might be fun to add a timer_type.modify(header) method as well that would return a new timer_types instance with the same type, but a different header.

[FIREdog5]

timer_type fields:
type
header

[FIREdog5]

it might make things easier as well if support was added for an optional header_data field