python: Adapt to Python 3 and add config for indentation size

lisp/init-python-mode.el

+;;; package --- Summary
+;;; Commentary:
+;;; Code:
 (setq auto-mode-alist
       (append '(("SConstruct\\'" . python-mode)
 		("SConscript\\'" . python-mode))
 
 (require-package 'pip-requirements)
 
+;; See: https://github.com/purcell/emacs.d/issues/724
+(setq python-shell-interpreter "python3")
+
+(setq-default python-indent 4)
+(setq-default python-indent-offset 4)
 
 (provide 'init-python-mode)
+;;; init-python-mode.el ends here