Adds template support for CCI Creation

This adds the ability to specify a template file to pull in options. The options will be merged with CLI-entered options with preference given to the CLI. An example of a CCI template is in SoftLayer/tests/fixtures/sample_template.conf.

Example template:
```
hostname = myhost
domain = example.com
datacenter = dal05
cpu = 4
memory = 1024
os = DEBIAN_7_64
network = 100
hourly = true
monthly= false
```

Example usage:
`sl cci create --template=test_template.cfg`
`sl cci create --os=DEBIAN_7_64 --cpu=2 --template=test_template.cfg`

This completes the CCI aspect of issue #142