* token: matches a sequence of bytes (with length)
* ch: matches a single byte
* range: matches any byte within the range [lower, upper] (inclusive)
* join_action: joins the results of another parser with a separator
* negate: matches the opposite of any single-character parser
* end_p: succeeds if there's no input left to parse
* nothing_p: always fails
One other big change: the AST is now a GSequence of parsed_token_t's. WARNING: This is not actually enforced, because C.
Also tweaked the makefile a little (which will get clobbered in TQ's next commit) and added some documentary comments to hammer.h.
