remove magic.diff from the source tree

magic entry for ctags is in upstream of file command:

	https://github.com/file/file/blob/master/magic/Magdir/ctags

We don't have to maintain it.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
docs: unify some documents to "hacking guide"

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
add README of fishman ctags

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
fix wrong order of inclusion lines

Signed-off-by: Masatake YAMATO <yamato@redhat.com>