merged adp_maze into maze, used page instead of mode

Cleaned up the separate level specifications in adp_maze.js
Now, instead of "mode", we use "page" just like karel
The levels.js contains all of the levels from adp_maze.js, so that file can removed.
Deferred indenting part of levels.js to reduce the diff until we all merge our changes.
Fixed changepegman to include the page in the URL
modified the en_us.json instructions string formats to match karel's page_level format

Note that some maze levels on page 2 duplicate levels on page 1 - by design. these can be cleaned up later. but in the interest of code cleanup, data separation, and symmetry with karel - this preserves the levels from adp_maze.js without all of the special logic.