Class FeatureDictListToMatrix

Constructor. Setup default parameter values.  

The following 3 attributes are used in the first pass through all feature dicts.
- componentdict1: A Map from features to their corresponding column number. 
- componentdict2: Inverse of componentdict1, ie, a Map from the column number 
                  to the corresponding feature.
- assignedcolumn: Total num of all feature columns.

- selectedFeatureNum: Number of selected features of interests.
- bitFlag: Boolean variable. if bits used, bitFlag=True. 
                             if counts used, bitFlag=False.

The following attributes are used in another pass through all feature dicts to 
get selected features.
- newComponentdict1: Similar to componentdict1, except that newComponentdict1 
                     only maps selected features to the corresponding column number.
- newComponentdict2: Inverse of newComponentdict1
- newAssignedcolumn: 

Return a matrix: MatrixNewA, which contains only selected features for all molecules.