add COMMAND_PARSE_BOOL macro and friends

add COMMAND_PARSE_BOOL macro and friends

Adds several macros similar to COMMAND_PARSE_NUMBER, but for parsing
boolean command arguments.  Two flavors are provided to provide
drop-in compatibility with existing code, allow for the elimination
of a lot of code bloat while improving the error checking and reporting.

COMMAND_PARSE_ON_OFF parses "on"/"off" command parameters.
COMMAND_PARSE_ENABLE parses "enable"/"disable" command parameters.

Both print the error and return an error out of the calling function.