* Removed purple warnings from unit test compilation.
* "Fixed const corectness bug. Added more warning fixes."
* Fixed warning issue.
* Removed null checking and (char*) casting.
* Changed sizeof parameter to variable from data structure.
Initial checkin of using udunits for measurement units conversions. Replaced
our conversion code in ICG and swig code to use udunits.
Also added code to convert unit symbols that we used in Trick that are different
names in udunits.
Added a sim_object that will eventually allow users to specify a custom
set of files to read units information.
refs #231
