Error on bad winsvc command
Restrict cassandra and hbase to linux and darwin
Stop logging on each batch sent
Init collect hostname correctly

Since Add and Set can now be called during init(), hostname should be set
during check instead of Init.
Use our standard init check method pattern for iis and sql

This prevents the log from getting spammed with exceptions every 15s.

The SQL collectors are also merged into one because it's simpler and they
didn't need to be separate.