Removed UIMenuController for editing sprites, added a way to select sprites in the canvas, and added the sprite editing to the toolbar.
Load methods from method manifest

Methods are now loaded from the method manifest. Created
new ZSZuseDSL (stands for Domain-Specific Language)
class which holds the canonical forms of statements and
expressions that the editor understands.
Merge pull request #73 from ZuseApp/method-manifest

Load methods from method manifest
Modified the sprite editing to lock all sprites but the one being edited.
Galaga mostly working (but crashing)

Fixed Galaga JSON so it can be listed amongst the demo
projects, but we don’t support the `every` statements
properly so it crashes in the editor.
Merge branch 'master' into edit-toolbar
Fixed Galaga JSON.
Removed duplicate line.
Factored out some code and removed empty method.
Merge pull request #74 from ZuseApp/edit-toolbar

Edit toolbar
Added menu to editor and ability to create string variables.
Editor changes.
mutableCopy replaced with deepMutableCopy
merged in master