Update gene input

[dan-knight]

These changes update the input format for gene data. The cn column has been changed to accept positive, negative and NA values instead of gain and loss strings. A boolean SNV column was added to allow genes to be differentiated with italicized text. The gene column was changed to a more generic name column.

Example Input Format

name	node	CNA	SNV
GENE1	1	1	FALSE
GENE2	1	-1	FALSE
GENE3	2	NA	TRUE
GENE4	1	-1	FALSE

Example Plot