Add support for multi-job Q and Configuration

This pull request combines commits from 2 people.  Please test thoroughly.  

## Multi-Job Q
Calling the `htcondor.q()` function without an id argument will return all jobs in the queue.  Documentation in the README.md is updated to reflect this change.

## Configuration
Condor may not be installed in the system PATH location.  A module configuration, through the `htcondor.config` dictionary is provided to allow for configuration of the Condor Location and the Condor Config location.  Documentation in the README.md is updated to reflect this change.