Prior to this commit a Component with setBufferedToImage (true) could
have its image buffer deleted when an OpenGL context was detached. This
meant that this Component continued to be rendered without buffering
even though it was previously requested that it use a buffer.
- Created a new detail namespace
- Moved shared module implementation details into the detail namespace
- Split dependencies so source files only rely on details in the detail namespace
- Removed all code from the juce_gui_basics.cpp file
