build for windows

[DanCech]

No description provided.

[Dieterbe]

for context of what happened in nsq, see nsqio/nsq#338
when we imported the nsq code - aug 4, 2014 via 293ca31 - it had already incorporated these changes, we just didn't copy over all files, probably because i never initially cared about windows support.
in particular we didn't copy nsqd/rename_windows.go, which at the time was the right implementation for windows (and the reason rename.go was protected with the !windows build flag is because doing that on windows resulted in all kinds of trouble, as the nsq PR explains)

However, digging a bit more through the nsq history, I found nsqio/nsq@95dac2a
which shows the go stdlib now solves this for us - as of 1.5 -, so we can most likely just remove all atomic_rename stuff in favor of simply os.Rename and it should work fine.
for more info see PR nsqio/nsq#844 and golang/go#8914 (comment)
I had some trouble verifying this (finding the relevant ticket or changelog)
and https://golang.org/doc/go1.5 doesn't mention this. https://golang.org/pkg/os/#Rename mentions nothing about windows, whereas other functions have documented windows exceptions (but it doesn't mention atomicity at all?)

if you want to increase confidence, you could go through nsq's changelog to see if anything else interesting changed (and/or see if we can just pull in more recent diskqueue code), or dig further into go's stdlib/docs/tickets

[Dieterbe]

silly github, i already left a comment

[DanCech]

Uh, what about the .gitignore and Makefile changes? want me to rebase this?

[DanCech]

Rebased it

[Dieterbe]

thanks Dan, sorry. moved a bit too quick on this.

[Dieterbe]

merged 👍