PERF: fix JSON performance regression from 0.12 (GH5765)
Merge pull request #6137 from Komnomnomnom/json-0.13-slowdown

PERF: fix JSON performance regression from 0.12 (GH5765)
DOC: v0.13.1.txt updates
BLD: use newer versions of numexpr with numpy 1.8
Merge pull request #6141 from jreback/numexpr

BLD: use newer versions of numexpr with numpy 1.8