Added custom errors, fixes to code generator

The code generator now handles okay the flags using True type
Also, double checking for the flag is now avoided in cases where the
flag was a Vector type

utils/binary_reader.py

@@ -1,6 +1,7 @@
 from io import BytesIO, BufferedReader
 from tl import tlobjects
 from struct import unpack
+from errors import *
 import inspect
 import os
 
@@ -16,7 +17,7 @@ class BinaryReader:
         elif stream:
             self.stream = stream
         else:
-            raise ValueError("Either bytes or a stream must be provided")
+            raise InvalidParameterError("Either bytes or a stream must be provided")
 
         self.reader = BufferedReader(self.stream)
 
@@ -96,11 +97,10 @@ class BinaryReader:
 
     def tgread_object(self):
         """Reads a Telegram object"""
-        constructor_id = self.read_int()
+        constructor_id = self.read_int(signed=False)
         clazz = tlobjects.get(constructor_id, None)
         if clazz is None:
-            raise ImportError('Could not find a matching ID for the TLObject that was supposed to be read. '
-                              'Found ID: {}'.format(hex(constructor_id)))
+            raise TypeNotFoundError(constructor_id)
 
         # Now we need to determine the number of parameters of the class, so we can
         # instantiate it with all of them set to None, and still, no need to write