general: remove inline qualifiers and move in-header functions to objects

* (general) Move functions in headers into files, to be compiled into
  shared object files. Remove inline qualifier from functions. Let the
  compiler do the work.
diff --git a/lib/thread.c b/lib/thread.c
index fd841c2..6d3c3cb 100644
--- a/lib/thread.c
+++ b/lib/thread.c
@@ -248,7 +248,7 @@
   XFREE (MTYPE_THREAD_STATS, hist);
 }
 
-static inline void 
+static void 
 vty_out_cpu_thread_history(struct vty* vty,
 			   struct cpu_thread_history *a)
 {
@@ -608,7 +608,7 @@
 }
 
 /* Thread list is empty or not.  */
-static inline int
+static int
 thread_empty (struct thread_list *list)
 {
   return  list->head ? 0 : 1;