Oops, make test_client support -m
Minor change: update documentation in chatserver
Performance improvements

Got rid of a memmove that was completely unnecessary (was needed in an
earlier incarnation and wasn't taken out when it should have been).
Also changed the utf8 decode table from uint8_t to uint32_t (both
changes informed by perf). According to perf, the autobahn performance
tests run about 10% faster overall (cpu-clock time).
Fix chat client

- The rooms table wasn't being populated correctly (had duplicate rows
  in some cases)
- The clients table wasn't working properly