update bluebird to cleanup handlers immediately after promise settlement.
removed hadron reference from comments.
Merge pull request #7 from HBOCodeLabs/makarand/cleanupHandlers

CHANGE SUMMARY

HAD-3334 bluebird's delayed handler cleans ups leads to memory leaks.
CHANGE DETAILS

our version of bluebird does not cleanup promise handlers immediately after promise is fulfilled. It waits for 256 handlers to have gathered before cleanup. Hadron uses some long lived promises - which is very legit usage of promises - which are then'ed by short lived objects. because of bluebird's delayed cleanup all those short lived objects do not get GC'ed. They account for substantial memory footprint.

This change changes the handler cache size from 256 to 1, now handlers gets cleaned up immediately on fulfillment.