CMake: dtoolbase/dtoolutil may need to link against Python.
CMake: Begin work on direct, get autorestart to compile.
CMake: Update Interrogate.cmake macro's use of COMPILE_DEFINITIONS:

- Slightly older versions of CMake default this to NOTFOUND, so test before iterating.
- Add to local definitions for building the _igate sources.
CMake: Interrogate/build nativenet, net.
CMake: Work on direct; get dcparse, dcparser, deadrec, directbase, distributed to build+Interrogate.
CMake: Update autorestart's CMakeLists to match the COMPILE_DEFINITIONS (rather than add_definitions) of the other components' CMakeLists files.
CMake: Get direct's 'interval' component library to build+Interrogate.
CMake: Add audio/movies components.
CMake: Build+Interrogate p3showbase.
Merge branch 'cmake' into cmake-cfs-direct

Conflicts:
	panda/CMakeLists.txt
CMake: Only build 'direct' if BUILD_DIRECT is on.
CMake: 'direct' depends on 'panda'
CMake: Only build 'autorestart' on UNIX.
Merge pull request #5 from kestred/cmake-cfs-direct

Get most of 'direct' building under CMake.