Updated iOS tests and demos for latest SDL linking requirements

Xcode-iOS/Demos/src/common.h

@@ -0,0 +1,10 @@
+/*
+ *  common.h
+ *  written by Holmes Futrell
+ *  use however you want
+ */
+
+extern int randomInt(int min, int max);
+extern float randomFloat(float min, float max);
+extern void fatalError(const char *string);
+extern double updateDeltaTime(void);