LBFGS optimier and new test cases for Poisson and Gamma regression

* Add LBFGS optimizer to both Poisson and Gamma regression models.
* Add real-world data set to the test suites. 
* Modify the ``generatePoissonInput()’’ method in test suite to generate multi-dimensional test data.


Both of us didn't use regParam in the updater. Do we want to remove this parameter or change SimpleUpdater to SquaredL2Updater or L1Updater?