1. Polish tabbing code.

1. Polish tabbing code.
2. Restore use of set_indentation_params(), was dead code since
   Autoindent.py was merged into EditorWindow.py.
3. Make usetabs, indentwidth, tabwidth, context_use_ps1 instance vars
   and set in EditorWindow.__init__()
4. In PyShell.__init__() set usetabs, indentwidth and context_use_ps1
   explicitly (config() is eliminated).
5. Add Tabnanny check when Module is Run/F5, not just when Checked.
6. Discourage using an indent width other than 8 when using tabs to
   indent Python code.

M EditorWindow.py
M NEWS.txt
M PyShell.py
M ScriptBinding.py