Fix bug in IP wildcarding.

    According to the OpenFlow specification, the mask on nw_src and nw_dst
    fields is not a description of how many bits to match, but rather a
    description of how many bits to mask. Hence, /0 is exact match and /32
    is a total wildcard.

    We had this backwards in the OpenFlow0x01 controller.

    This pull requests fixes the bug.
Remove trailing whitespace, break long lines, remove other spurious whitespace
trivial whitespace edits
Merge pull request #172 from frenetic-lang/mask-more-bugfix

    Fix bug in IP wildcarding.