Return error rather than panicking on malformed json where there are more closing brackets than opening brackets

Author: HC Hagen

parser.go

@@ -343,6 +343,12 @@ func EachKey(data []byte, cb func(int, []byte, ValueType, error), paths ...[]str
 		case '[':
 			var arrIdxFlags int64
 			var pIdxFlags int64
+
+			if level < 0 {
+				cb(-1, []byte{}, Unknown, MalformedJsonError)
+				return -1
+			}
+
 			for pi, p := range paths {
 				if len(p) < level+1 || pathFlags&bitwiseFlags[pi+1] != 0 || p[level][0] != '[' || !sameTree(p, pathsBuf[:level]) {
 					continue