Remove redundant check

This if() is already within an if() that checks the same thing

Change-Id: Id0d69ce34a6de212a67952a3ba6bd1e03f3bacb0
Modify lists in-place instead of making new lists

This was is about 2x as fast on normal-sized lists (5-10 items) and
5x as fast for really large lists (1000s of items)

Change-Id: I9fee2e6d6750f15ec4242f6989d89393419c5cdd
remove unused hash

Change-Id: If7f808039a26bc8bdb84a12b522baaf3ce4ba3fe
both names refer to the same function

Change-Id: I2eec018d0bee93db7a14c3d4d146eb9a56aeb7de
$property_set is always a ref from 2 lines above

Change-Id: Ia49e6c483565173dc77d779ebb1f4e5b060fef54
Fix bug

Shouldn't ever use "my ... if ..." constructs

I'm not sure what conditions would trip the problem, but it'll be hard to
debug if it did happen.

Change-Id: I5d95f687b408f0193d9bdc87708fa189e8d13030
Turn these subs in UR::Util into functions from methods

UR::Util isn't a class, and these aren't methods.  It should speed up
calling these functions a tiny bit, too.

Change-Id: If0b25c5d3216051a23b91139afd9283f9e55649b
Merge pull request #32 from amb43790/boolexpr

More efficient boolexprs