Added process_id_t and thread_it_t types to the server interface
instead of using void*, and removed a number of type casts.

diff --git a/server/snapshot.c b/server/snapshot.c
index c9a1225..562f901 100644
--- a/server/snapshot.c
+++ b/server/snapshot.c
@@ -73,7 +73,7 @@
 
 
 /* create a new snapshot */
-static struct snapshot *create_snapshot( void *pid, int flags )
+static struct snapshot *create_snapshot( process_id_t pid, int flags )
 {
     struct process *process = NULL;
     struct snapshot *snapshot;