Build system: Move template-based debian build into debian-template

We are going to want to introduce a real Debian source package build
system.  But that needs to contain a lot of things in debian/ which
ought not to appear in the .deb made by the existing ad-hoc `./build
debian' arrangements, which we want to keep so as not to unduly
disturb existing users.

So rename the whole debian/ directory to debian-template/ and change
all references in the build system.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

build

@@ -77,15 +77,15 @@ fi
 
 if [ x$1 = "xdebian" ]; then
   here=`pwd`
-  cd debian/wiringPi
+  cd debian-template/wiringPi
   rm -rf usr
   cd $here/wiringPi
   make install-deb
   cd $here/devLib
   make install-deb INCLUDE='-I. -I../wiringPi'
   cd $here/gpio
-  make install-deb INCLUDE='-I../wiringPi -I../devLib' LDFLAGS=-L../debian/wiringPi/usr/lib
-  cd $here/debian
+  make install-deb INCLUDE='-I../wiringPi -I../devLib' LDFLAGS=-L../debian-template/wiringPi/usr/lib
+  cd $here/debian-template
   fakeroot dpkg-deb --build wiringPi
   mv wiringPi.deb  wiringpi-`cat $here/VERSION`-1.deb
   exit