Merge pull request #4924 from cpcloud/eval-datetime-in-python

ENH: evaluate datetime ops in python with eval
API: Remove deprecated read_clipboard/to_clipboard/ExcelFile/ExcelWriter from pandas.io.parsers (GH3717)
Merge pull request #5009 from jreback/remove_io_deprecate

API: Remove deprecated read_clipboard/to_clipboard/ExcelFile/ExcelWriter from pandas.io.parsers (GH3717)
ER: give concat a better error message for incompatible types
Merge pull request #5011 from cpcloud/concat-err-msg

ER: give concat a better error message for incompatible types
DOC: prior version section in v0.13.0
BUG: Fix a bug when indexing np.nan via loc/iloc (GH5016)
ENH/CLN: Give AssertionErrors and nose.SkipTest raises a message
Merge pull request #5018 from jreback/column_nan

BUG: Fix a bug when indexing np.nan via loc/iloc (GH5016)
ER: give a better error message for hashing indices
Merge pull request #3730 from cpcloud/parse-exceptions

ENH/CLN: give all AssertionErrors and nose.SkipTest raises an informative message
Merge pull request #5019 from cpcloud/raise-on-index-hash

ER: give a better error message for hashing indices
FIX #4554 and other issues with Series.reshape()
added halflife to exponentially weighted moving functions
DOC: make experimental functionality more visible in release notes
Merge pull request #5037 from cpcloud/exp-rls-notes

DOC: make experimental functionality more visible in release notes
TST: added null conversions for TimeDeltaBlock in core/internals related (GH4396)
TST: chmod -x on pandas/computation/tests/test_eval.py
CLN: Refactor arithmetic operations to core/ops

* Abstract all arithmetic methods into core/ops
* Normalize arithmetic methods signature (see
  `ops.add_special_arithmetic_methods` and `ops.add_flex_arithmetic_methods`
  for signature).
* Opt-in more arithmetic operations with numexpr (except for
  SparsePanel, which has to opt-out because it doesn't respond to
  `shape`).
* BUG: Fix ``_fill_zeros`` call to work even if TypeError (previously
  was inconsistent).
* Add bind method to core/common
* Add full range of flex arithmetic methods to all NDFrame/ndarray
  PandasObjects (except for SparsePanel pow and mod, which only work for
  scalars)
* Add a set of testing methods to check that numexpr was actually used
  successfully.
* Flesh out test cases to include all arithmetic ops + test refactoring
* Disable numexpr for sparse objects (they don't work correctly right
* now)
* Sparse methods aren't moved because they are very specific to sparse
  (and aren't numexpr accelerated)
* Disable r* comparisons for now because they cause test failures
* Specifically allow radd in TimeOps for Series
* Fixup Series time rops and add a few test cases.
* Disable flex r-ops for bools (no good test cases yet...)
* TST: Remove tests for TypeErrors in pandas/computation/test_eval that
  now work after this refactor (because DataFrame now defines more r*
  methods)
BUG: Fix DateOffsets to return NotImplemented when types do not match

Enable test cases that involve these DateOffsets with `__r*` ops