OT namespace 129 --> 134

129-133 are already in use (according to example.h)
put child hash generation in own function

(will be used somewhere else in weight-based approach)
OT::clear_cycle impl matches name

used to be xor, meaning a toggle
OT::create_new_features had unused variable

(it was only used in a commented out debug print)
online_tree --- minor formatting fixes

(only making things consistent, not imposing any FENCHEL)
online_tree cleaning: clear_features rename

clear_features --> clear_cycle_many
since it just calls clear_cycle in a loop.
online_tree:  initial (buggy) weight-based

still needs lots of work; point of patch is basic conditional wrapping
of regret-based