Converted the build system to non-recursive automake

Signed-off-by: Gabriele Svelto <gsvelto@mozilla.com>
Reworked the rules to build the manpages and extra documentation

- Man-files renaming is now handled automatically by automake
- The rules for building XML/HTML documentation would often work
  erratically, now they're invoked only as part of the dist targets
- Added quiet rules for asciidoc invocations

Signed-off-by: Gabriele Svelto <gsvelto@mozilla.com>
Fixed out-of-tree builds when using the included openpgm library

Signed-off-by: Gabriele Svelto <gsvelto@mozilla.com>