GC-91: Adding new implementations/ports for two new versions of the L-BFGS optimizer:
 - The updated bounded optimizer available in Lbfgsb.3.0, and
 - The updated L-BFGS library with support for Orthant-Wise optimizer in LibBFGS.

Several tests still have to be implemented and the interfaces must be corrected to try avoiding breaking changes.
GC-91: Adding several new unit tests and a testing framework for comparing the LibBFGS implementation against the framework sources.

More tests are still needed for the bounded L-BFGS sources.
GC-91: Linking the original Lbfgsb3 library against the unit tests project in order to write more unit tests for the BoundedBroydenFletcherGoldfarbShanno optimizer.
GC-91: Starting to get the first Lbfgsb3 tests working.
GC-91: Lbfgsb3 tests now work.
GC-91: Working on documentation, normalizing optimizers interfaces and preparing room for GC-63.
GC-91: Refactoring of the function optimization methods. Optimization methods don't throw exceptions anymore.
GC-91: Working on unit tests and documentation.