remove last_previous from NoErrorTokenizer
remove NoErrorTokenizer dependency for all but the fast parsers
moved NoErrorTokenizer to fast.FastTokenizer
remove some old parameters from Parser and FastTokenizer
remove unnecessary checks
start using tokens all the way through in the parser
parser: remove current
use the module end_pos in fast parser
protect start_pos/end_pos in parser to hopefully remove them soon
successfully removed end_pos from parser
removed Parser._start_pos as well
finally removed self-contained iterator from Parser - after knowing this since almost the beginning.
remove offset param for Parser
start using @ganwell's new token class (modified in some ways) as the main token class - hope to gain a little bit of memory/cpu/pickling performance