v0.5.0-pre2-test

Destructuring support

When jrsonnet-evaluator is built with exp-destruct (And in this pre-release - it is), syntax proposed here is supported (see last comment):
google/jsonnet#307

It was implemented as part of large optimization implementation, now locals in objects are cached not per field, but globally. I.e

{
  local a = std.trace("get a", 1),
  b: a,
  c: a, 
}

Earlier, manifestification of this object would print get a 2 times, but now it will be printed only once