Merge pull request #2857 from lodagro/issue_2854

TST: avoid platform dependency, close #2854
thanks!
TST: update describe_option to report default and current value
BLD: bring back build_ext warning message cython is missing #2439
BLD: use 1.7.0 final in travis py3.3 environment
BUG: fixup GH #2751; make sure that we cast to platform numeric
     when a list is specified; use the Series codepath
     for initial list conversion (change from using DataFrame)
TST: added test for overflow in df creation
DOC: RELEASE and whatsnew updated for DataFrame from lists change
CLN: cleaned up _possibly_convert_platform
CLN: moved some functionality from series._sanitize to com._dtype_from_scalar
DOC: whatsnew updates
CLN: in common.py merged _dtype_from_scalar and _infer_dtype
     yield _infer_dtype_from_scalar
CLN: in common.py - revised _maybe_upcast to use _maybe_promote
     in rehashpe.py - removed block2d_to_block3d in favor of block2d_to_blocknd
ENH: provide boolean indexing with dtype preservation if possible
ENH: return dtype on invalid function in where is now float64
BUG: fixed bug in IntBlock splitting
     bug in internals.Block.putmask ; coercing unecessarily
TST: force rebuild
CLN: change call signature of _maybe_promote (from stephenwlin branch)
     and _infer_dtype_from_scalar to match (both return dtype, fill_value)

Diff between 'jreback/dtypes_bug' and 'stephenwlin/dtypes_bug'

Conflicts:

	pandas/core/common.py
Merge pull request #2846 from stephenwlin/fix-maybe-convert-objects

BUG: Various issues with maybe_convert_objects (GH #2845)
thanks!
Merge branch 'dtypes_bug' of https://github.com/jreback/pandas into jreback-dtypes_bug

Conflicts:
	pandas/tests/test_frame.py
CLN: add fill_value return value to common._maybe_promote
ENH: Consolidate and further improve performance of take functions