Windows support

[simonbyrne]

I tried to build on Windows, but hit issues with this:

tempestremap/src/triangle.cpp

Lines 834 to 835 in 31e51ff

	/* triangles are four-byte-aligned and that the `unsigned long' type is */
	/* long enough to hold a pointer are two of the few kludges in this program.*/

On Windows, unsigned long is 32 bits even on 64 bit platforms. It could either be changed to unsigned long long, or uintptr_t (included in <stdint.h> from C-99).