Add fixed functions numRows and numCols.
had to rename variables for numRows example
Change the names of some variables.
Merge pull request #293 from BayesianLogic/rows_cols

Add methods numRows() and numCols()
make sure there are at least 2 components

If there's only one component, we can't initialize the Dirichlet
distribution, because the parameter is a 1x1 matrix.
Merge pull request #296 from BayesianLogic/fix-example

make sure there are at least 2 components
Merge branch 'master' into continuous-integration.
This was done to get fix for adaptive-background-mixture.dblog