Fix importing dependencies during installing (#384)

setup.py

@@ -15,16 +15,11 @@ Extra supported commands are:
 from codecs import open
 from sys import argv
 import os
+import re
 
 # Always prefer setuptools over distutils
 from setuptools import find_packages, setup
 
-try:
-    from telethon import TelegramClient
-except Exception as e:
-    print('Failed to import TelegramClient due to', e)
-    TelegramClient = None
-
 
 class TempWorkDir:
     """Switches the working directory to be the one on which this file lives,
@@ -94,21 +89,15 @@ def main():
         fetch_errors(ERRORS_JSON)
 
     else:
-        if not TelegramClient:
-            gen_tl()
-            from telethon import TelegramClient as TgClient
-            version = TgClient.__version__
-        else:
-            version = TelegramClient.__version__
-
         # Get the long description from the README file
         with open('README.rst', encoding='utf-8') as f:
             long_description = f.read()
 
+        with open('telethon/version.py', encoding='utf-8') as f:
+            version = re.search(r"^__version__\s+=\s+'(.*)'$",
+                                f.read(), flags=re.MULTILINE).group(1)
         setup(
             name='Telethon',
-
-            # Versions should comply with PEP440.
             version=version,
             description="Full-featured Telegram client library for Python 3",
             long_description=long_description,