Updated TODO.
Updated TODO.
Cleaning up MaterialPackageManager main menu.
Consolidated MaterialPackageWrangler tests.
Implemented MaterialPackageManager.configure_autoeditor().

Also implemented MaterialPackageManager.remove_autoeditor().

MODEL: The purpose of the methods will be to configure a material package for
management by an editor class. This replaces the old idea of 'manager-made'.
Previously there was a distinction between 'handmade' and 'manager-made'
material packages. Now there are just material packages. And a material package
may be configured for autoediting or not.
Removed 'materials - make new for editable mainline class' (nmc) command.

Use 'materials - new' (new) instead. Then use 'package - configure autoeditor'
(pca) to set up autoediting for the package you created.
Extended MaterialPackageManager main menu.

Example:

    Red Example Score (2013) - materials

        1: magic numbers (Red Example Score)
        2: pitch range inventory (Red Example Score)
        3: tempo inventory (Red Example Score)

        materials - copy (cp)
        materials - new (new)
        materials - remove (rm)
        materials - rename (ren)

    >

The (cp), (rm) and (ren) commands now accompanying the existing (new) command.
Removed where-tracking.

No longer necessary.

Use 'session - display variables' (sdv) instead.
Removed SourceCodeContext context manager.

No longer needed.
Merge pull request #375 from tiagoantao/master

Div stuff plus a slice case
Adjusted CyclicTuple coding style.
Harmonized wrangler make_*() method names.
Removed Wrangler.select_asset_package_path().

No longer needed.
Updated TODO.
Renamed private Wrangler method.

OLD: Wrangler._get_current_directory_path_of_interest().

NEW: Wrangler._get_current_directory_path().
Tightened manager initialization.

Managers must now initialize with a path that is not none.
Removed manager path-is-none checks.

Manager path is never none.
Refactoring menu section initialization.

MenuSection will eventually force all menu entry definition to happen at
initialization.

This will make menu sections much more like constant objects that can not
change after initialization.
Refactoring menu section initialization.
Refactoring menu section initialization.