Module "builders" to "extenders"

[Andrus Adamchik]

Just squeezed an 11th hour change before we freeze the Beta:

https://github.com/apache/cayenne/commit/175ec07f69446ea89c8ed8ec338b29d45f95821e
https://github.com/apache/cayenne/commit/ab6554dc6412dda640ebfcd6a4797cb0a1193f5f

The goal is to eliminate a new API inconsistency. With the introduction of 
auto-lodable modules, classes that we used to call FooModuleBuilder no longer 
build a FooModule. The module is loaded automatically and can not be changed. 
The corresponding "builder" builds a separate custom module with extensions. 
This pattern is present in:

1. CommitLogModuleBuilder
2. CacheInvalidationModuleBuilder
3. CryptoModuleBuilder
(4. OsgiModuleBuilder... if we make it auto-loadable)

Instead of a builder there's now an "extender", which is otherwise analogous to 
the builder, and the invocation looks like this:

  Module extensions = 
     CommitLogModule.extend().addListener(mockListener).module();

I changed #1, and if there are no objections will change #2 and #3. 

Andrus