Improved underscore method validation

Introduces some complicated function-wrapping
to try to make it harder for players to call
underscore methods on map in their code (i.e.
methods they shouldn't have access to anyway)
minor
beginning to validate callbacks
lots of fixes to validation -- primarily getting exits and lvl15 to work
callback validation - getting dynamic objs, lvl7 to work
adding checks to unexposed player and dynamicObject methods
fixing lvl17 by wrapping player._moveTo in teleporter def
Added some solutions to the list.
Ask for confirmation on the ^4 reset.
New solution for level 06
Merge branch 'esolitos-new_solutions'
not sure if I'm merging all these solutions together correctly
merge
Merge branch 'amahdy-patch-6'
getting ready for big merge
Merge branch 'better_underscore_checking' of github.com:AlexNisnevich/untrusted into better_underscore_checking
Increased the reset timer to 2.5s
Ref. #221
Merge pull request #221 from esolitos/reset-needs-confirm

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Merge pull request #236 from AlexNisnevich/better_underscore_checking

Better underscore checking
fix lvl21