async+perf: ch1, 'interaction'
async+perf: ch1, more on sync blocking vs async
async+perf: ch1, more on 'interaction' concurrency
types+grammar: tweaking parenthetical for clarity
async+perf: ch1, lots of tweaks/clarifications, more on 'interaction' and 'cooperation' in concurrency
async+perf: ch1, note about ES6 hosting the event-loop now
types+grammar: adding mention in appendix-A about 'console' host object
async+perf: ch1, adding discussion of async 'console', and 'statement reordering'
async+perf: ch2 intro
async+perf: ch2, 'continuations'
async+perf: ch2 'sequential brains'
async+perf: ch2, nested callbacks, trust issues
async+perf: ch2 tweaks
async+perf: more content in ch2 about callback issues
async+perf: more to ch2, including 'trying to save callbacks'
async+perf: adding link to ch2 into README
async+perf: fixing some code bugs in ch2
async+perf: starting ch3
async+perf: ch2, adding some explanations of 'callback hell' phrase
async+perf: tweaks to ch1 and ch2 text