Some new math blocks
Name/description tweaks
Add gcd and lcm blocks
Add factorial/gamma
Add min and max
Rebuild
shortcuts added
Update undo.js

For mac user, event for pressing cmd key is added

'cmd + z' for copy
'cmd + x' for undo
get examples running again
add more examples to the menu
Fixed issues with values

Values were described as fractions when they should have been decimals.
Merge pull request #514 from waterbearlang/504-Sandbox-Game

504 sandbox game