updated imbalanced training

scdiff_1.1.15

updted imbalanced training

Updated with more visualization functions and changed cutoff for DE genes

Added more visualization functions:

1. Integrated PANTHER and Toppgene GO analysis
2. Added more 2D visualizations of the scRNA data (PCA, t-SNA ISOMAP)
3. reduce the DE fold change cutoff from 1.5 to 1.0