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

srcpkgs/udev/files/udev.initramfs-bottom

@@ -0,0 +1,24 @@
+#!/bin/sh -e
+# initramfs premount script for udev
+
+PREREQ=""
+
+# Output pre-requisites
+prereqs()
+{
+	echo "$PREREQ"
+}
+
+case "$1" in
+    prereqs)
+	prereqs
+	exit 0
+	;;
+esac
+
+
+# Stop udevd, we'll miss a few events while we run init, but we catch up
+pkill udevd
+
+# Move /dev to the real filesystem
+mount -n -o move /dev ${rootmnt}/dev