Fix cqlsh dtests on windows

There are a number of portability problems with python on win32 as I've learned over the past few days.

• Our use of multiprocess is broken in cqlsh for windows.

https://docs.python.org/2/library/multiprocessing.html#multiprocessing-programming

The code was passing self to the sub-process which on windows must be pickleable (it's not). So I refactored to be a class which is initialized in the parent.
Also, when the windows process starts it needs to load our cqlsh as a module. So I moved cqlsh -> cqlsh.py and added a tiny wrapper for bin/cqlsh

• Our use of strftime is broken on windows

The default timezone information %z in strftime isn't valid on windows. I added code to the date format parser in C* to support windows timezone labels.

• We have a number of file access issues in dtest
• csv import/export is broken on windows and requires all file be opened with mode 'wb' or 'rb'

http://stackoverflow.com/questions/1170214/pythons-csv-writer-produces-wrong-line-terminator/1170297#1170297

• CCM's use of popen required the univeral_newline=True flag to work on windows