Pls review fixes for issues 36,52: changes to build: skip missing opt parts
Please review the fix of of issues:
36: Make dependencies on javacomm and glassfish optional.
52: Revised patch for excluding JUnit from build
New target "opt" is added.
Being run as "ant opt" build allows jcommjar, servletjar, junitlib to be unset. When property unset the corresponding classes will be excluded from compilation.