Standardize parentheses around require/include statements

[nacin]

99.9% of the time, require and include (and *_once) statements don't need parentheses.

All but about 10 instances, these statements use parenthesis. We should either remove all of them (personally, less parentheses is always good) or make it a coding standard to always have them, and add them to the remaining instances.

[johnbillion]

Cleaning out a few tickets. Unless this is going to be patched there's no point in leaving the ticket hanging around open.