Infer correct types for lambdas and anon methods

[hopscc]

Lambdas and anon methods/closures should have their types inferred correctly as method sigs not "dynamic" and anon method return type respectively.

Probably should be a follow on from patch for ticket:39 using same
method sig search and matching.

[hopscc]

Fix for this relies on code in patch for ticket:39 and is included in second patch
ref-lambda-type-inference.patch on that ticket