Merge pull request #120 from jsolman/master

util.gettimeofday() returns values too large for string.format("%d")
Fixed typo in documentation.
More work on module creating guide.
Merge branch 'master' of https://github.com/kernelsauce/turbo
Further improve speed of mime base64 encoding routines.
Base 64 decode is a little faster than libb64 on my AMD FX6100, and
a very slightly slower (a few percent) for encoding.  The speeds of
encoding and decoding are both approximately 4x faster than before
these changes.

Also optamize util.gettimeofday() and util.gettimemonotonic().