Change the configure-based MPM build mechanism to support building an MPM as a shared shared or dynamic module, primarily using the APACHE_MPM_MODULE() function. --enable-mpms-shared now builds/installs the MPMs as dynamic modules. (But no LoadModule directives are added.)

Remove all signal handling from the worker MPM's child processes. Instead, we use the pipe of death for all communication between parent and child.

Add the worker MPM. The name is probably horrible, but I couldn't come up with anything better. This is a multiple-worker/single listener MPM. This MPM is definately not complete, but it is a first step in the right direction.