I have /usr/local/bin in my PATH and so I was finding swig there.
Running configure through brew does not include /usr/local/bin.
I changed the test to look for swig in a set of directories we
normally use.
refs #66
Added /usr/local to the list of search directories in the configure script
for the motif header files. Added -lc++abi to the list of link libraries.
refs #66
Replaced our handmade configure script with one created with autoconf. Added a config_user.mk.in file that is populated with the output of a configure. Some platform specific makefile assignments that never change are included in the files config_Darwin.mk and config_Linux.mk.
refs #13