Add GDS Verify module changes

GDS Verify(IDA) project use a fork of this graphite module. It seems like a good idea to incorporate changes in to this module, with the view the Verify project dropping the fork and using only this module.

The GDS Verify additional changes are:
 - Ability to specify the user used to run the processes
 - Install from Debian package
 - Some carbon cache options
Two things here.

1. Why do you need to add `install_args`? It's not clear that you need this. Also, if it not required, there would be no need for lines 21-27.

2. You added `install_args` in 9f4559148. That commit doesn't explain why they've been added; and it also does several other things (as you note in the commit message). Please could you rebase that commit to separate out the different changes into different commits? This makes it much easier when reviewing the history (e.g. when looking for the explanation of a change).