Remove extra parens from conditionals

This patch changes various conditionals with unnecessary parens like:

    if(sys.platform.startswith("win32")):

to more idiomatic Python:

    if sys.platform.startswith("win32"):

I don't usually submit patches with style changes, but most of the conditionals in this project don't have the extra parens.  Removing these oddballs makes the code overall more consistent, and perhaps a little easier for Python programmers to read.