Add variable for python interpreter.

[zmward99]

I was trying to use this package with a new system that doesn't have python2.7, and figured it would be easier to set the interpreter with this variable.

[benma]

This package is supposed to work with all Python versions, including python2 and python3. What was the issue that you ran into exactly?

[zmward99]

The python interpreter on my machine is called python3, and rather than changing the long string variable (vr--command-python-default) to call the correct python version, I created a variable that can be set to either python or python3. It's prepended onto the vr--command-python-default variable.

[benma]

Thanks. In this case you should add another defcustom var which can be customized using customize-variable - the vr-- vars are considered internal.

Not sure what happens when you use one defcustom var inside another (vr/command-python in this case) - ideally the default for it would then be using the variable as customized by the user. I think this is what would happen but I am not quite sure.