Parse -0 correctly. Fixes SBJson#88.

Author: stig

Classes/SBJsonTokeniser.m

@@ -257,7 +257,11 @@ - (sbjson_token_t)getNumberToken:(NSObject**)token {
             return sbjson_token_eof;
     }
 
+    unsigned long long mantissa = 0;
+    int mantissa_length = 0;
+    
     if (ch == '0') {
+        mantissa_length++;
         if (![_stream getNextUnichar:&ch])
             return sbjson_token_eof;
 
@@ -267,9 +271,6 @@ - (sbjson_token_t)getNumberToken:(NSObject**)token {
         }
     }
 
-    unsigned long long mantissa = 0;
-    int mantissa_length = 0;
-
     while ([digits characterIsMember:ch]) {
         mantissa *= 10;
         mantissa += (ch - '0');

Tests/Data/valid/number/integer/input

@@ -2,6 +2,7 @@
 -98877665544332211009988776655443322110,
 -1,
 0,
+-0,
 1,
 98877665544332211009988776655443322110
 ]

Tests/Data/valid/number/integer/output

@@ -1 +1 @@
-[-98877665544332211009988776655443322110,-1,0,1,98877665544332211009988776655443322110]
+[-98877665544332211009988776655443322110,-1,0,0,1,98877665544332211009988776655443322110]