add some type hints (commaai#774)

* type stubs for common, parser_pyx

* Cleanup imports

* values are indeed floats

* common.pyi complete, added cpp stubs

* parser_pyx.pyi complete

* CANPacker completed

* Holding temp changes...

* remove *.pyi

* just remove skip-file

Co-authored-by: Jason Shuler <jshuler@gmail.com>

can/packer.py

@@ -1,3 +1,2 @@
-# pylint: skip-file
-from opendbc.can.packer_pyx import CANPacker
+from opendbc.can.packer_pyx import CANPacker # pylint: disable=no-name-in-module, import-error
 assert CANPacker

generator/generator.py

@@ -10,12 +10,12 @@
 generated_suffix = '_generated.dbc'
 
 
-def read_dbc(src_dir, filename):
+def read_dbc(src_dir: str, filename: str) -> str:
   with open(os.path.join(src_dir, filename)) as file_in:
     return file_in.read()
 
 
-def create_dbc(src_dir, filename, output_path):
+def create_dbc(src_dir: str, filename: str, output_path: str):
   dbc_file_in = read_dbc(src_dir, filename)
 
   includes = include_pattern.findall(dbc_file_in)
@@ -39,7 +39,7 @@ def create_dbc(src_dir, filename, output_path):
     dbc_file_out.write(core_dbc)
 
 
-def create_all(output_path):
+def create_all(output_path: str):
   # clear out old DBCs
   for f in glob.glob(f"{output_path}/*{generated_suffix}"):
     os.remove(f)