[sugar etiona] Reduce ISO size by pruning unnecessary things

The size of the ISO could be reduced by removing some stuff that's not necessary:

66MB /usr/src/linux-headers
184K /usr/include/btrfs
13MB man-db and /usr/share/man
29MB /usr/share/doc
72KB /usr/share/bug
62MB /var/cache/apt/*.bin (apt-get auto-rebuilds these)
80MB /usr/share/locale (by running localepurge keeping the supported languages)
----
250MB

/usr/share/doc does contain a slew of copyright notices, but I am assured by quozl that the copyright terms are still valid without these.

These are not enough to make it fit on a CD, but might help get it under 1GB instead of being just over. I know you can't now buy a new pendrive less than 8GB but I'm using a 2GB one so I'm sure some people only have 1GB devices.