Capsule cache should support multiple versions of an application/CAPSULE_ID

[timpatt]

Currently the capsule cache uses the CAPSULE_ID (usually the application name) as a key to the cache. This causes issues if there are multiple versions of the capsule in existence with the same CAPSULE_ID.

We've often had issues where after upgrading our application capsule, the cache - which contains an older version of the same application - is still used.

A simple (?) solution to this may be to add a hash of the capsule's contents to the capsule during creation and append this to (or use in place of) the CAPSULE_ID in the cache. Versioning then no longer becomes an issue!