BUG: not processing TypeError on reading some json (so was failing rather than trying not-numpy for dtypes)
ENH: added convert_axes argument to control whether to coerce axes

ENH: changed dtype argument to accept a dict for a per-column dtype conversion, or
     turn off conversion (default is True)

ENH: changed parse_dates to convert_dates, now defaulting to True

BUG: not processing correctly some parsable JSON
TST: tests for numpy=True/False differeing in parsing
PERF: changed default to numpy=False to have correct parsing using unordered JSON

      eliminated fallback parsing with numpy=True; This will raise ValueError
      if it fails to parse (a known case are strings in the frame data)
Merge pull request #3876 from jreback/json_rt

ENH: JSON