Major infrastructure changes, part 2.

* Moved helpers, common and triggers dirs into xbps-src, where
  they belong.
* Renamed the templates dir to srcpkgs, it was so redundant before.
* Make it possible to add subpkgs with no restriction in names, for
  example udev now has a subpkgs called "libgudev". Previously
  subpkgs were named "${sourcepkg}-${pkgname}".
* xbps-src: changed to look for template files in current directory.
  That means that most arguments from the targets have been removed.
* xbps-src: added a reinstall target, to remove + install.
* xbps-src: do not overwrite binpkgs by default, skip them.

And more that I forgot because it's a mega-commit that I've been
working for some days already...

--HG--
extra : convert_revision : 0f466878584d1e6895d2a234f07ea1b2d1e61b3e

templates/babl/patches/fix_extensions_rpath.diff

@@ -1,11 +0,0 @@
---- extensions/Makefile.in.orig	2009-08-17 11:06:49.321238565 +0200
-+++ extensions/Makefile.in	2009-08-17 11:06:59.065205114 +0200
-@@ -242,7 +242,7 @@ AM_CPPFLAGS = \
- 	-I$(top_srcdir)/babl		\
- 	-I$(top_srcdir)/extensions
- 
--extdir = $(DESTDIR)$(libdir)/babl-@BABL_API_VERSION@
-+extdir = $(libdir)/babl-@BABL_API_VERSION@
- ext_LTLIBRARIES = \
- 	CIE-Lab.la      \
- 	gegl-fixups.la  \