Stats fixups

[rumblesan]

This PR cleans up a few things around the stats widget.

• Stats widget is no longer passed all the way into core. there's an event that's fired after every succesfully animated frame that a listener hooks into to update the widget.
• Added a 'livecodelab-sleeping' event which is now hooked into to trigger hiding the stats widget.
• LiveLang V2 now has better comment handling and is better at figuring out if a sketch is empty.

fixes #142 fixes #146

[rumblesan]

@davidedc I'm currently making the assumption here that an "empty" sketch is one that's comprised only of comments and white space. You mentioned in #142 about the edge case of supporting non-rendering sketches, but I'm not sure that's something worth supporting currently.

[davidedc]

yeah if detecting non-rendering code doesn't fit the solution easily, let's not do it

[rumblesan]

it's not necessarily that it's difficult to do, more that I don't think it's worth supporting. I think that the best example of non-rendering code is for straight audio sketches, but even then LCL is "doing something" so having some form of stats up still seems reasonable.

[davidedc]

yes you are right, we'd also have to check if a "play" command is issued, not just graphical commands.

But let's keep it simple, let's do as you say, it's not worth the additional complication even if it's just one flag.

[rumblesan]

fair enough. One thing is that currently the livelangv1 compiler only checks if a sketch is totally comprised of white space, it doesn't handle comments, so a sketch of just comments still displays the stats.

Shouldn't be too tricky to update the regexp checker though I think

[rumblesan]

right, got it, and with a test as well :)