ENH: add percentile_width to describe method in series and dataframe
merge, resolve conflicts
Merge branch 'master' of https://github.com/pydata/pandas
Merge branch 'master' of https://github.com/pydata/pandas
Merge branch 'master' of https://github.com/pydata/pandas
Merge remote branch 'origin/master'
Merge branch 'master' of https://github.com/pydata/pandas
Merge branch 'master' of https://github.com/pydata/pandas
DOC: update docstring for DataFrame.to_csv
TST: add test for to_csv/from_csv inf and nan roundtrip
ENH: allow to_csv to save nans and infs
BUG: in maybe_convert_numeric, if you've seen an 'inf', you've seen a float
TST: check for -inf dtype as well as +inf
BUG: 0/0 and nan/0 should equal nan
ENH: make None/NaN different from INF/-INF (GH #1919)
ENH: special option for writing infs in csvs no longer needed
ENH: add method use_inf_as_null to core.common (GH #1919)
DOC: update docs about null/missing values
Panel4D is like a Panel object, but provides 4 dimensions: labels, items, major_axis, minor_axis

instead of using a dict of Panels to hold data, the Panel4D provides a convenient represenation in pandas space
 with named dimensions to allow easy axis swapping and slicing

testing
-------

tests/test_panel4d.py provides a similar methodology to test_panel.py

Panel4D required an overhall of many methods in panel.py and one change in core/index.py (regarding multi-indexing)
 almost all methods in a Panel are extended to Panel4D (with the exception in that Panel now allows a multi-axis on axis 0)

docstrings need to be refreshed a bit and made a bit more general

all tests that are not skipped pass (tested with 0.9rc1)

join is a work in progress

further
-------

panelnd.py provides a factory function for creation of generic panel-like ND structures with custom named dimensions
  (this works, but not fully tested - examples are in the docstring)
fixed file modes