fixed signed-unsigned issue from 166

Loss of entropy can be discussed at a later time, but is
not deemed a significant issue for now.
initial doxygen commenting of the CryptoNight proof-of-work code
More documentation
fix typo
another typo fix
Merge pull request #167

aeaa44f fixed signed-unsigned issue from 166 (Thomas Winget)
Merge pull request #170

46f26ff another typo fix (David G. Andersen)
ac6bc48 fix typo (David G. Andersen)
d744dd1 More documentation (David G. Andersen)
4d493f6 initial doxygen commenting of the CryptoNight proof-of-work code (David G. Andersen)
added static build dependency instructions to README
Merge branch 'master' of http://github.com/fluffypony/bitmonero