Use CODE BEGINS only for YANG files starting with ietf-.
Add yinx->yang processing step.
Shorten README and refer to wiki.
Adjust master branch.
Fix README.
Migrate reference handling to XInclude.
Revert "Migrate reference handling to XInclude."

This reverts commit f120a71390d15cb77a711404bc10b598e3fa7fdb.
Update the reference extraction stylesheet.
Add automatic generation of standard references.
Add empty stdrefs.ent file.
Fix gen-refs stylesheet.
Decouple compiling of references.
Make refs target dependent on other entuty files.
Add dependency of refs.
Add YINX -> YANG stylesheets.
Add entity with another RFC ed. hint.
Add area name.
Add text about RFC 2119 keywords.
Add module boilerplate.
Fix generation of YANG from YINX.