We had an unintentional conflict with PixelBuffer::setSize() here.
But we can simplify this further as this initialization is only used
by the subclass DeviceFrameBuffer, and only once.

This will allow us to use better formats that preserve the entire
alpha channel.

Gets rid of a loooot of code and complexity.

Colour map clients are still supported through an
automatically generated map, but we lose the ability to
develop a client or server that uses colour maps
internally.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@591 3789f03b-4d11-0410-bbf8-ca57d06f2519

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/branches/merge-with-vnc-4.1.1@523 3789f03b-4d11-0410-bbf8-ca57d06f2519

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@2 3789f03b-4d11-0410-bbf8-ca57d06f2519