doc: fix missing backtick in 2e16037
doc: improve module documentation

Expands on when to use module.exports vs. exports. This is a recurring
question on mailing list and continues to confuse new devs.
doc: fs: clarify fs.symlink Windows specific args
npm@1.3.13
Merge remote-tracking branch 'ry/v0.10'
dgram: send() can accept strings

Strings passed to Socket#send() will be passed to Buffer and parsed as
UTF8.