Color picker crash fix.

Color arrays in RNA are 4 floats but handlers used 3 floats. Overflow galore.

source/blender/editors/interface/interface_intern.h

@@ -377,7 +377,7 @@ struct uiPopupBlockHandle {
 	int butretval;
 	int menuretval;
 	float retvalue;
-	float retvec[3];
+	float retvec[4];
 };
 
 uiBlock *ui_block_func_COL(struct bContext *C, uiPopupBlockHandle *handle, void *arg_but);

source/blender/editors/interface/interface_regions.c

@@ -1597,7 +1597,7 @@ static void do_picker_rna_cb(bContext *C, void *bt1, void *unused)
 	uiPopupBlockHandle *popup= but->block->handle;
 	PropertyRNA *prop = but->rnaprop;
 	PointerRNA ptr = but->rnapoin;
-	float rgb[3];
+	float rgb[4];
 	
 	if (&ptr && prop) {
 		RNA_property_float_get_array(&ptr, prop, rgb);