Improve PEG performance

[presidentbeef]

• Fix how rule names are tracked/applied (no need for hash table)
• Simplify rule-level match caching (arrays instead of hashes, inlined code)
• Simplify parse-level match caching (array instead of hash) (note this is only needed to clear rule caches when re-using parser)
• Above changes removed need for complicated rule closure and object creation for each rule

Performance

Times below are in seconds. Only parse time is included. Average of 10 runs.

File	Before	After	Change
peg.brat (7.8kb)	3.009703	2.351904	-22%
invoke_helper.brat (15kb)	3.570489	2.696362	-24%
parser.brat (14kb)	5.05334	3.235386	-36%
life.brat (1.1kb)	0.803088	0.312095	-61%