Fixes #75 new write_data_grid() method in data_grid.h has problem compiling under windows
* Conversion from std::string to char* solved by adding invokeing c_str().
* Changing the data type of data_size from size_type* to long* seems to fix the second problem. Apparently, size_type is a short in Win32 and netCDF is hardcodes to use longs for sizes.
Merge branch 'master' of https://github.com/campreilly/UnderSeaModelingLibrary