Fixes for issues 21 and 22 on Github to not include unistd.h on Windows and to use correct linkage specifier for expat function names for static builds
Fix for issues 21 and 22 on github. This removes use of unistd.h on windows and correctly includes expat for static builds
correct definition of dram, per CEG-308566

While the fluid dram specification is ok, the plain dram is:
* an avoirdupois unit of mass (and so should not be based on fluid ounces) [1] [2]
All references to the use of dram as a fluid measure call it a 'fluid dram' (and make it 1/8 fluid ounces).  

This changes the definition was changed and moves the result into the mass section.

[1] National Institute of Standards and Technology (October 2011). Butcher, Tina; Cook, Steve; Crown, Linda et al. eds. "Appendix C – General Tables of Units of Measurement", page C-6
[2] WIkipedia entry https://en.wikipedia.org/wiki/Dram_(unit)
Fixed _progname pointing to stack memory and left dangling. Also fixed possible buffer overrun when _progname is assigned on Windows.
Merge branch 'master' of https://github.com/philrosenberg/UDUNITS-2
updated definitions in .xml files
fixing minor conflict
Adjust pull-request changes
Merge branch 'philrosenberg-master'
Add comments and, definitions and correct "dram"
Add "fluid_dram"
Merge branch 'graybealski-master'