Add support for windows (VC2013)

Fix some existing bugs :
 cryptonight hashrate log and lock when missing stratum diff

colors: enable colored output by default

and also trap signals on windows (Ctrl+C)

Current state: much slower than linux (and x64 almost twice the x86 speed)

Signed-off-by: Tanguy Pruvot <tanguy.pruvot@gmail.com>