ENH: support for msgpack serialization/deserialization

DOC: install.rst mention

DOC: added license from msgpack_numpy

PERF: changed Timestamp and DatetimeIndex serialization for speedups

      add vb_suite benchmarks

ENH: added to_msgpack method in generic.py, and default import into pandas

TST: all packers to always be imported, fail on usage with no msgpack installed
DOC: added mentions in release notes, v0.11.1, basics

ENH: provide automatic list if multiple args passed to to_msgpack

DOC: changed docs to 0.12

ENH: iterator support for stream unpacking
ENH: added support for Panel,SparseSeries,SparseDataFrame,SparsePanel,IntIndex,BlockIndex