Experimental lexer generator: rename_things(Dfa minimization) += comments part 2

Experimental lexer generator: rename_things(Dfa minimization) += comments part 2

- id_map -> state_to_id
- reverse_id_map -> id_to_state
- __merge_partitions -> __create_states_from_partitions
- name_map -> partition_to_name
- reverse_partition_map -> state_id_to_partition
- mapping -> partition_name_to_node
- transition_id -> transition_state_id (moar)
- x -> state_id
- map_into_partition -> states_transitioning_to_test_partition (still not a great name)

BUG=

Committed: https://code.google.com/p/v8/source/detail?r=17904

[marja, 2013-11-20 10:31:23]

Committed patchset #5 manually as r17904.