add docstring; bump to v2.1

Author: tomchen

src/bdfparser/__init__.py

@@ -1,3 +1,9 @@
-__version__ = "2.0.0"
+'''
+BDF (Glyph Bitmap Distribution Format) Bitmap Font File Parser in Python
+Copyright (c) 2017-2021 Tom CHEN (tomchen.org), MIT License
+https://font.tomchen.org/bdfparser_py/
+'''
+
+__version__ = "2.1.0"
 
 from .bdfparser import *