VB: cut down worst runtime offenders in vb suite
BLD: test_perf, progress indicator, catch kb interrupts
BLD: test_perf, progress indicator, catch kb interrupts
BLD: add --ncalls to test_perf, to override excessive runtimes in vbench
BLD: test_perf, adjust column widths
BLD: test_perf, print pickle filename if specified
BLD: test_perf, supress Futurewarnings, DeprecationWarning
Remove the duplicated test cases
Merge pull request #3184 from waitingkuo/fix-append-empty-frame

BUG: Append the empty frame with columns, #3121
TST: Log scale on bar chart hides bars GH3247
BUG: Log scale on bar chart hides bars GH3247
DOC: update RELEASE.rst
DOC: cookbook examples courtesy of @timmie
DOC: cleanups
Merge pull request #3248 from y-p/doc_io_cleanups

DOC: io.rst cleanups
Merge pull request #3245 from jreback/GH3243

BUG: GH3243 accept list of DataFrames as constructor input
BUG: df.plot(grid=None) (was False), obey mpl's default style GH3223
BOOK: keep code examples in wes's book current, until the 2nd ed.
Merge pull request #3250 from y-p/book

BOOK: keep code examples in wes's book current, until the 2nd ed.
Revert "TST: Log scale on bar chart hides bars GH3247" mpl 1.2.1 regression

This reverts commit 682b39ed851c272aef4872dc59571c4266cd2ff4.