Removed initialization code to set the screen size and replaced it by a

Removed initialization code to set the screen size and replaced it by a
separate module that contains a module constructor. In some cases, the
code was even unnecessary, since the screen size is known in advance.

git-svn-id: svn://svn.cc65.org/cc65/trunk@476 b7a2c559-68d2-44c3-8de9-860c34a00d81