Add "mod_macro" as a standard module, compiled in with "most". This module was created in 1998 and has been distributed independently ever since. It is hereby donated to the Apache Software Foundation. There are quite a few comments in the source code to explain how it works, as well as extensive non regression tests. Some utilities about array processing could be moved to "core.c". However, I finally decided against for now so that it stays as an external and independent module, and thus may be backported with minimal impact on the source tree. Details of the addition: * modules/core/mod_macro.c: module source code * modules/core/test: non regression tests modules/core/test/conf/: configuration files modules/core/test/ref/: expected results * docs/manual/mod/mod_macro.xml: English documentation * docs/manual/mod/mod_macro.xml.fr: French documentation