* refactor
* fix: bug in previous refactor
* chore: exclude phpcompat sniff due to bug in phpcompat
* fix: do not leak absolute paths
* refactor/fix: batch extensions checking, fix DOS issue
This moves the responsibility for getting a valid class name
to the users of BridgeFactory, avoiding the repeated sanitation.
Improper use can also be checked statically.
The bridge factory can be based on the abstract factory class if it
wasn't static. This allows for higher abstraction and makes future
extensions possible. Also, not all parts of RSS-Bridge need to work
on the same instance of the bridge factory.
References #1001
