Add examples from published paper

[touste]

As a new Simit user, it would be nice to have more examples, such as the elastic shell simulation presented in the paper.
Thanks!

[fredrikbk]

Forgive the late reply (we've been focusing hard on the compiler for Simit (taco) and have been too unresponsive of late). I've added the cloth code of @evouga in 1706c88. In addition bc902bf merges a port of Lulesh by @Lugatod .

[fredrikbk]

We are also working on an ARAP optimization code that we hope to make available the next few weeks.

[touste]

Thanks, this is really helpful!