Add the headerfiles to the generated project files

Change-Id: I0a82af82a6bee74a21942346b268e249205a0d9b
Reviewed-on: http://review.couchbase.org/33992
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>