Isolate Source directories in CMake build

Isolate Source directories in CMake build
https://bugs.webkit.org/show_bug.cgi?id=148389

Reviewed by Brent Fulgham.

.:

* CMakeLists.txt:
* Source/cmake/WebKitCommon.cmake:
Move package finding to WebKitCommon.

Source/JavaScriptCore:

* PlatformWin.cmake:
Include ../include/private to find WTF headers in internal build.
Don't use a script to generate forwarding headers.
* shell/PlatformWin.cmake:
Copy inspector scripts to the forwarding headers directory to be used by WebCore.

Source/WebCore:

* CMakeLists.txt:
Use the forwarding header copy of the inspector scripts to avoid requiring JavaScriptCore directory to exist.
* PlatformAppleWin.cmake:
Add AVFoundation sources to build.
* PlatformEFL.cmake:
Moved WebKitVersion.h generating from CMakeLists.txt because it is now only used in WebCore by EFL.
* PlatformWin.cmake:
Include ../include/private to find forwarding headers in internal build.

Source/WebKit:

* PlatformWin.cmake:
Moved WebKitVersion.h generation from WebCore because the scripts required for it are in WebKit.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@189056 268f45cc-cd09-0410-ab3c-d52691b4dbfc