Fixed up bug with encode_application_double function.

Added new bacapp_decode_application_data_safe function and other *_safe functions that aim to prevent buffer overruns if encoded application message is malformed.
Note: bacstr unit tests currently have one failure.

bacnet-stack/include/bacreal.h

@@ -42,6 +42,11 @@
 extern "C" {
 #endif /* __cplusplus */
 
+	int decode_real_safe(
+		uint8_t * apdu,
+		uint32_t len_value,
+		float *real_value);
+
     int decode_real(
         uint8_t * apdu,
         float *real_value);
@@ -56,7 +61,12 @@ extern "C" {
     int decode_double(
         uint8_t * apdu,
         double *real_value);
-    int encode_bacnet_double(
+	int decode_double_safe(
+		uint8_t * apdu,
+		uint32_t len_value,
+		double *double_value);
+
+	int encode_bacnet_double(
         double value,
         uint8_t * apdu);