Add compilation test for standalone inclusion of openjpeg.h (#798)

This ensures all openjpeg.h dependencies are met.
Fix #673

tests/include_openjpeg.c

@@ -0,0 +1,9 @@
+#include <openjpeg.h>
+
+int main(int argc, char **argv)
+{
+	(void)argc;
+	(void)argv;
+	
+	return 0;
+}