Assure compatibility between components' versions

[KirilKabakchiev]

Assure that components (Proxies and SM) are "compatible"

1. On startup of a component - some compatibility check should be performed against the "linked" counterpart based on versions. If check fails, strartup should fail (ex. Starting proxy -> compatibility check against the SM that is presented as SM_HOST, the check verifies that proxy and SM both specify the same "version" or specify different compatible versions))
2. Compatibility tests ran on travis build to validate newly released sm/ proxy works with the currently released / deployed counterpart / component. (ex. releasing new version of CF proxy -> during travis build some compatibility tests may be performed that use a particular release of service manager (the used service manager should be compatible with the new proxy release)