BUG: Changes types used in packing structs

Types used for integer conversion where always half the size they should be.  
Produced a bug when exporting data tables with long integer data (np.int64).
Added test for integer conversion bug

Added test for incorrect integer conversion from int16, int32 and int64
Removed unintended whitespace
Fixed another typo
Added test for integer conversion bug

Added test for incorrect integer conversion from int16, int32 and int64
Fixed another typo
FIX: Corrected incorrect data type conversion between pandas and Stata
FIX: Remove unnecessary, potentially precision degrading cast to Series when writing data
ENH: Added function to cast columns from NumPy data types to Stata data types
FIX: Corrected tests for correct Stata datatypes
Fixed formatting in comparison after casting
Added docstring for new function and warning class
BUG: Changes types used in packing structs

Types used for integer conversion where always half the size they should be.
Produced a bug when exporting data tables with long integer data (np.int64).
Added test for integer conversion bug

Added test for incorrect integer conversion from int16, int32 and int64
FIX: Corrected incorrect data type conversion between pandas and Stata
FIX: Remove unnecessary, potentially precision degrading cast to Series when writing data
ENH: Added function to cast columns from NumPy data types to Stata data types
FIX: Corrected tests for correct Stata datatypes
BUG: Changes types used in packing structs

Types used for integer conversion where always half the size they should be.
Produced a bug when exporting data tables with long integer data (np.int64).
Added test for integer conversion bug

Added test for incorrect integer conversion from int16, int32 and int64
Fixed another typo
Removed unintended branch merge
Merge branch 'stata-export-datatype' of https://github.com/bashtage/pandas into stata-export-datatype

Conflicts:
	pandas/io/tests/test_stata.py