Export symbols in order to support shared libraries (#54)

* Add BAC_ROUTING compile definition

* Reorder cmake

* Fix OpenSSL support: support both 1.0 and 1.1t pus

* Explicitly export symbols, hidden by default

* Build shared libraries on travis using cmake

* Learn Makefile about static library

* Fix build using mingw with cmake

* Do not cleanup twice or after potential free

src/bacnet/authentication_factor.h

@@ -28,6 +28,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include "bacnet/bacnet_stack_exports.h"
 #include "bacnet/bacdef.h"
 #include "bacnet/bacapp.h"
 
@@ -42,16 +43,20 @@ typedef struct {
 extern "C" {
 #endif /* __cplusplus */
 
+    BACNET_STACK_EXPORT
     int bacapp_encode_authentication_factor(
         uint8_t * apdu,
         BACNET_AUTHENTICATION_FACTOR * af);
+    BACNET_STACK_EXPORT
     int bacapp_encode_context_authentication_factor(
         uint8_t * apdu,
         uint8_t tag,
         BACNET_AUTHENTICATION_FACTOR * af);
+    BACNET_STACK_EXPORT
     int bacapp_decode_authentication_factor(
         uint8_t * apdu,
         BACNET_AUTHENTICATION_FACTOR * af);
+    BACNET_STACK_EXPORT
     int bacapp_decode_context_authentication_factor(
         uint8_t * apdu,
         uint8_t tag,