Fix CMake on Linux case sensitivity problem
Update Code-Eli to latest master.

Includes fix for X11 collision with Eigen on Linux.
Change library linking order to get VSP to build on Linux
Add pthreads on Linux
Add -fPIC flag for x86_64 on Linux.

The Position Independent Code flag is needed for shared libraries on some
platforms.  This is normally implied for shared libraries, but we build
most of VSP as static libraries, so it is not set automatically.

Later, we use these static libraries to build a shared library for the
Python bindings.  So, for dual-use libraries, we need to set -fPIC manually.
Re-order libraries for Python bindings.
Merge remote-tracking branch 'ramcdona/v3_Alpha' into v3_Alpha