[Evolution] Spurious include files

[Federico Mena Quintero <federico helixcode com>]

Right now evolution/addresbook/backend/pas is installing a bunch of
header files that I think are only for the PAS library's internal
use.  If that is the case, they should be removed and put in
noinst_HEADERS in the Makefile.am instead.  It also installs the EBook
stuff under $(includedir)/backend; see below.

(The PCS does the same, but I am fixing it so that it does not install
the private header files.)

Also, we are installing $(includedir)/{composer,backend,cal-client}
directories with a bunch of header files.  This may be polluting the
namespace a bit.  Should we create $(includedir)/evolution/{foo,bar,baz}/*.h
instead?

Camel does install $(includedir)/camel, but since it is supposedly not
tied to Evolution (is it?), I guess it is OK to install its header
files there.

On the library side, maybe libpas/libpcs should be built only inside
Evolution and not installed; their only purpose in life is to become
parts of Wombat and nothing else.

Paranoids-R-us,

  Federico