List every handler's dependencies in the long description.

This makes it clear what package(s) one must install in order to use any given
handler.

The devscript package's long description served as an example of how we can deal
with shipping that many tools and only suggesting their individual dependencies,
without going through the overhead of shipping every single handler in its own
binary package.

debian/control

@@ -25,4 +25,14 @@ Description: lightweight, extensible meta-backup system
  .
  Backupninja currently supports common backup utilities, easing their 
  configuration, currently supported are: rdiff-backup, duplicity, CD/DVD
-
+ .
+ Most handlers have their own dependencies/recommendations, shown in brackets
+ bellow:
+ .
+  - dup [duplicity]
+  - rdiff [rdiff-backup]
+  - sys [debconf-utils, hwinfo, mdadm]
+  - makecd [genisoimage, wodim]
+  - rsync [rsync]
+  - svn [subversion]
+  - tar [bzip2]