pitchscreen make it a plugin

full commandline parsing
    -has pitch, speed, time_stretch
 /* pitch_screen
 *  accepts args -q, -g, -p=, -s=, -k=; (= sign is optional)
 * -q silences output splash
 * -g runs the gui (Runs immediately)
 * -p100 would set pitch to 100%
 * -s=90 sets speed to 90% if timestrech is enabled
 * -k=true -k1 enables time stretch -k0 -kf-kn disables
*/

Change-Id: I900c4b5d184e12ddbe47509f66fdf3e55193a520

apps/plugins/lib/arg_helper.c

@@ -28,7 +28,9 @@
 
 #define SWCHAR '-'
 #define DECSEPCHAR '.'
-
+#ifdef PLUGIN
+    #define strchr rb->strchr
+#endif
 int string_parse(const char **parameter, char* buf, size_t buf_sz)
 {
 /* fills buf with a string upto buf_sz, null terminates the buffer