Totally refactored source files location

Now it *should* be easier to turn Telethon
into a pip package

telethon/tl/session.py

@@ -0,0 +1,64 @@
+from os.path import isfile as file_exists
+import os
+import time
+import pickle
+import random
+import telethon.helpers as utils
+
+
+class Session:
+    def __init__(self, session_user_id):
+        self.session_user_id = session_user_id
+        self.server_address = '91.108.56.165'
+        self.port = 443
+        self.auth_key = None
+        self.id = utils.generate_random_long(signed=False)
+        self.sequence = 0
+        self.salt = 0  # Unsigned long
+        self.time_offset = 0
+        self.last_message_id = 0  # Long
+        self.user = None
+
+    def save(self):
+        """Saves the current session object as session_user_id.session"""
+        if self.session_user_id:
+            with open('{}.session'.format(self.session_user_id), 'wb') as file:
+                pickle.dump(self, file)
+
+    def delete(self):
+        """Deletes the current session file"""
+        try:
+            os.remove('{}.session'.format(self.session_user_id))
+            return True
+        except:
+            return False
+
+    @staticmethod
+    def try_load_or_create_new(session_user_id):
+        """Loads a saved session_user_id session, or creates a new one if none existed before.
+           If the given session_user_id is None, we assume that it is for testing purposes"""
+        if session_user_id is None:
+            return Session(None)
+
+        else:
+            filepath = '{}.session'.format(session_user_id)
+
+            if file_exists(filepath):
+                with open(filepath, 'rb') as file:
+                    return pickle.load(file)
+            else:
+                return Session(session_user_id)
+
+    def get_new_msg_id(self):
+        """Generates a new message ID based on the current time (in ms) since epoch"""
+        # Refer to mtproto_plain_sender.py for the original method, this is a simple copy
+        ms_time = int(time.time() * 1000)
+        new_msg_id = (((ms_time // 1000 + self.time_offset) << 32) |  # "must approximately equal unixtime*2^32"
+                      ((ms_time % 1000) << 22) |  # "approximate moment in time the message was created"
+                      random.randint(0, 524288) << 2)  # "message identifiers are divisible by 4"
+
+        if self.last_message_id >= new_msg_id:
+            new_msg_id = self.last_message_id + 4
+
+        self.last_message_id = new_msg_id
+        return new_msg_id