async+perf: tweaking note in ch3, per #229
async+perf: starting on appendix-A, 'advanced async patterns'
fix typo
async+perf: moving appendix B to C
async+perf: lots more work on appendixA about 'asynquence'
Merge pull request #230 from chenxsan/fix-typo

fix typo
async+perf: apA, more on asynquence
async+perf: lots more in appendix-A
async+perf: finishing up appendix-A on 'asynquence'
async+perf: appendix-A, tweaking wording
async+perf: starting on appendix-B, about 'iterable sequences'