BUG: fix typeerror caused by spurious call to len on frame multiindex
unicode of PeriodIndex returns valid Python code
fix for 3.2 which does not accept unicode literal prefix
Merge pull request #3557 from cpcloud/html-typeerror-bug-fix

fix TypeError for display.multi_sparse == False
TST: to_html regards empty string labels as repeated labels GH3547
BUG: to_html regards empty string labels as repeated labels GH3547
Merge branch 'GH3547'

* GH3547:
  BUG: to_html regards empty string labels as repeated labels GH3547
  TST: to_html regards empty string labels as repeated labels GH3547
DOC: update RELEASE.rst
Merge pull request #3560 from cpcloud/period-index-unicode-evaling-3460

ENH: unicode of PeriodIndex returns valid Python code