Split old LDA.py script into LDA.py and LDA_bubble.py.
Error handling for explained variance calculation and, consequently,
plot X and Y labels added, in addition to input file error checks.
LDA_bubble.py is compatible with both Python2 and Python3.

Moved bubble plot calculation and plotting to LDA_bubble.py script.
Updated package imports and import error check.
Removed get_relative_abundance() function.
Relative abundance calculation is done using PhyloToAST util module.
Expanded plot_LDA() function to accommodate new input parameters.
Added 3D plotting capability and X and Y axis label checks for variance
calculations.
Reorganized and updated input parameters.
Updated input file error handling.
Script is compatible with Python 2 and Python 3 syntax.

Added documentation file for LDA_bubble.py script.
Added LDA_bubble script to complete script list page.
Generalized distance matrix help message.

Updated LDA script command line description.
Generalized distance matrix help message.
Updated documentation file for LDA.py script.
Added LDA_bubble script to visualization page in documentation.