fix 2 minor grammar mistakes in README.md
Merge pull request #380 from strugee/master

Make a slightly ambiguous statement in the README less ambiguous
Use GET to get Campfire rooms, not POST

There's no need to use POST when fetching a room from Campfire, and
doing so risks running up against Campfire's POST rate limit (50 POSTs
in 5 seconds).
version bump to 2.3.5 for campfire fix