Changes:
* CHECK_STRIKES macro now takes a comma-delimited list of strike counts for when units have a different number of strikes for different weapons, and updates the existing usage in the attacks tests
* Fixed a typo in the attacks_zero test
* Adds tests for berserk as a weapon special ability.
Berserk's handling differs from attacks as a weapon special ability:
* A value less than 1 is treated as effectively infinite rounds of combat (undocumented)
* The cumulative attribute is handled differently - in some cases it sums the values instead of using the highest single value whereas for attacks it always uses the highest single value
Also now exclude data/tests/ from scons pot-update since it was hitting the argument limit for number of arguments to a script.
so far only the stuff in po/ is done, what has to be done next is add
the textdomain to the respective file and run a pot-update
the current po files are based on the files from the textdomain
'wesnoth' since this is where the strings currently reside, after the
pot-update only the relevant strings will be left
