Suggestion: allow users to add phASER as a path

[bozbezbozzel]

Requiring phASER to be part of the $PATH makes it harder than it needs to be to integrate vcfMerger2 into snakemake (for example). An option to provide a path to the built local version pf phASER would be appreciated. Thanks for all your work.

[bozbezbozzel]

I've now added my own ugly fix by changing PHASER_EXE=phaser.py ; ## phASER requires python2.xx (not 3) to include the full path to the phaser executable.