Allow named blocks in risu config files; restrict blocks to end of line
Allow named blocks in risu config files; restrict blocks to end of line

Force blocks in risu config files to be at the ends of lines. Allow
them to be named (with an unnamed block being a constraints block
for backwards compatibility). At the moment the only recognised
block is "constraints".

vivier/risu,stsquad/risu,vivier/risu,stsquad/risu,hw-claudio/risu-aarch64,stsquad/risu,hw-claudio/risu-aarch64