Changed tokens with underscores and alphabetic characters to be parsed as ID, instead of WORD, and changed tests to reflect this.
Added simple versions of common rules which should be used for rules that can't parse complex types due to the use of various operators like '-', '+', '*', and '.'.
Fixed up commands so that HOSTNAME can be recognized as a field (valid because it appears in queries, and HOSTNAME is like an ID, but with periods in it).