Change transaction fee and reward calculations.

[a-urth]

#232 #233

Also changed naming for collapse_test

[AhmadMuzakkir]

Looks good.

[rkeene]

This looks good to me after some testing. A few issues remain:

1. The total reward may not be exactly the same as the total fee (though the total reward will never exceed the total fee, so it is not a huge deal)
2. There is no test that verifies that withdrawal requests work -- we did this experimentally and it worked. There is no test because in older versions it was harder to get the reward triggered, but now it is deterministic.