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

network/tcp_transport.py

@@ -2,6 +2,7 @@
 # https://github.com/sochix/TLSharp/blob/master/TLSharp.Core/Network/TcpTransport.cs
 from network import TcpMessage, TcpClient
 from binascii import crc32
+from errors import *
 
 
 class TcpTransport:
@@ -42,7 +43,7 @@ class TcpTransport:
         valid_checksum = crc32(rv)
 
         if checksum != valid_checksum:
-            raise ValueError('Invalid checksum, skip')
+            raise InvalidChecksumError(checksum, valid_checksum)
 
         # If we passed the tests, we can then return a valid TcpMessage
         return TcpMessage(seq, body)