[travis] gcc 4.9
[travis] Use older swig.
[travis] Fix swig directory error.
[swig] omit superfluous virtual method definitions

http://www.swig.org/Doc1.3/Modules.html

Trying to reduce size of generated source code.
[travis] Build with less jobs

Hoping to fix gcc failure.
Update .travis.yml
[travis] build only osimJavaJNI.
[travis] With gcc, build osimJavaJNI first.
[travis] Fix bug in bash if statement.
[travis] Speed up build for gcc.
[travis] Remove -fvirtual flag.
[travis] For gcc, build only osimJavaJNI first.
Merge pull request #134 from opensim-org/travis-gcc-crash

Important thing is it builds and passes. So I am merging it. We can open another issue to streamline the travis build. Maybe by leaving out the JNI build from gcc? Let's discuss.