udated to use current elixir.
docs say elixir upwards of (>=) 0.13.3 is supported, tests show current elixir is supported, mix.exs said elixir *up to* (~>) 0.13.3 is supported. changed mix.exs accordingly
fixed a crash where the bot would choke on a missing colon after its name. also removed a couple of instances of a hardcoded botname, instead of the bot_name variable from the config.
the crash was due to a divergence between lines 17 and 27. the bot would look for its name, but then try to split the received data at its name surrounded by colons. If you started your message with the bots name *without* following it up with a colon, it would crash because the split would turn up empty.
Merge pull request #13 from chrifpa/fix/crash

Fix/crash