Tweaked Makefile rules; added includes/sections.inc
added layouts/standard.inc
Fixed problems in includes/sections.inc
Moving layout details out of the main script

Almost all done. Now we have:
presets/standard.inc: page dimensions, padding, margins and stuff like that
includes/sections.inc: definitions of which sections are available
layouts/standard.inc: locations and dimensions of each section
Completed moving out definitions

Layouts and the like are fully moved out to external files.
Merge branch 'external-boxes-definitions'