coming soon: consistency checking scripts

We'll shortly be committing a script to do checking for consistency between our OVAL and XCCDF. This should detect situations such as:

1) a reference from an XCCDF rule to an OVAL definition that doesn't exist.

2) an XCCDF rule exists (and is used in a profile) but doesn't include any reference to a check.

3) mismatch between filename and OVAL definition name (as this is an important convention for our approach to modular definitions)

4) others?