Revert "Redmine#3323: @include mechanism"

This reverts commit 3fc17367cb1ad78a007a41a8a554ac3f5566fb63.

Conflicts:
	libpromises/cf3lex.l
	libpromises/cf3parse.y
Merge pull request #1301 from tzz/revert/@include

Revert "Redmine#3323: @include mechanism"