Merge branch 'maint'

Merge branch 'maint'

* maint:
  build: don't enable 'color-tests' automake option explicitly
  build: enable all warnings as fatal in our own build system
  texi: Texinfo sources and CLEANFILES definition should co-exist peacefully
  tests: make two new test executable
  runtest: better command line API
  tests: move runtest.in away from the top-lever directory
  maint: move more maintainer files in the 'maint/' subdir
  tests: more significant names for some tests
  maint: add some of my maintainer-specific scripts
  texi: deprecate hack about info files in CLEANFILES variables
  texi: info files can be generated in the builddir