Temporarily remove references to global variable in crash monitor,
which prevents linking against libcvmfs.cc
Added test program to verify that libcvmfs.a can be linked against C executables.
Merge pull request #194 from cooperative-computing-lab/master

test_libcvmfs

Added a program to test the libcvmfs C interface.
Commented out a link-time problem in the cvmfs monitor.
Fixed some minor issues in the libcvmfs.h header.