Remove Google Drive as default drive for release.py

[qlquanle]

From the last meeting we agree that we should allow user to specify a release directory that is not Google Drive. My sense is that we can do that by changing

release.py line 35

    USER = os.environ['USER']
    if branch == 'master':
        name   = repo
        branch = ''
    else:
        name = "%s-%s" % (repo, branch)
    local_release = '/Users/%s/Google Drive/release/%s/' % (USER, name)
    local_release = local_release + version + '/'

where we move USER and local_release to user_config.yaml.

@lboxell, I think you're the most familiar with this code out of current lab members and are least likely to unintentionally break something while working with it. Do you want to make this change? I can do it as well. Thanks!

[qlquanle]

PR #72