Fix pluralization error
Qualify "Bitcoin {=>Core} 0.9"
Merge pull request #61 from cbeams/edit-3

Correct minor errors
Merge remote-tracking branch 'saivann/dev' into moreautoxref

Conflicts:
	en/developer-guide.md
Merge branch 'moreautoxref' of https://github.com/harding/bitcoin.org into moreautoxref