Remove trailing whitespace.
Add missing semicolons.
Use reply from _chain arguments instead of message.
Merge #25 r=@johnnyman727: Fix _chain replies

Makes possible to use alternate starts in `_chain` command. Current code seems to replace them with message for some reason.

Original commit for that: https://github.com/tessel/gprs-sim900/commit/e8bc444513f007e1d1c57289511b3e93e31dceba