Problem: doc/Makefile appears in configure.ac even when not generated
Solution: remove from configure.ac when count (class) <= 0
Problem: General code for resolution of dependencies is in build-autoconf.gsl
Solution: Move all dependency-resolution code to class_projects.gsl
Problem: pc.in for project does not list all requires
Solution: get requires list from "for project.use"
Problem: Autoconf test for dependency "zyre" is not from zyre
Solution: Use "zyre_test" as configure test
Problem: configure.ac has code copied from czmq that is not general
Solution: Remove the czmq-specific configurations
Merge pull request #25 from jemc/nodoc

Problem: Some generator scripts are still inconsistent
Merge pull request #27 from jemc/pc-in_requires

Problem: pc.in for project does not list all requires