Fix fees overwrite in starkware plugin (#198)

* increase display buffer size to handle Starkware master key and control size when using snprintf

* Bump version 1.9.6

* Fix broken tests

* Add first starkware tests

* Add some constants for starkware

* Update CHANGELOG.md

src/shared_context.h

@@ -166,7 +166,7 @@ typedef enum {
 
 typedef struct txStringProperties_t {
     char fullAddress[43];
-    char fullAmount[50];
+    char fullAmount[67];
     char maxFee[50];
     char nonce[8];  // 10M tx per account ought to be enough for everybody
     char network_name[NETWORK_STRING_MAX_SIZE];