Remove pathlib dependency. (#1)

`pathlib` is not available in python 2.7; `format.py` will crash in that
situation. The easiest solution is to just remove the dependency on
`pathlib` and use `os.path.splitext` which seems to be supported by both
python 2 and python 3

Co-authored-by: Iwan <[email protected]>

Author: IwanKaramazow

format.py

@@ -4,7 +4,6 @@
 import re
 import os
 import tempfile
-import pathlib
 import platform
 
 SETTINGS_PATH = 'Default.sublime-settings'
@@ -187,7 +186,7 @@ def run(self, edit, formatBuffer=True):
     if bscExe == None:
       return
 
-    extension = pathlib.Path(filename).suffix
+    _, extension = os.path.splitext(filename)
     formattedResult = formatUsingValidBscPath(
       code,
       bscExe,