(PUP-3117) Allow multiple *=> in the same body and error on duplicate

This fixes a problem in the grammar that made it impossible to have
more than one *=> per body. 

This commit also adds a check for duplicate entries in the resulting
hash with the final set of parameter to value mapping.
(PUP-3117) Add tests for combination of default / hash
(maint) Make PuppetSpec::Language emit more helpful stack traces

This change was required to be able to see anything relevant regarding
where a problem originated. The fix is to patch the stacktrace
for failed expectencies. While not ideal there is very little that can
be done with Rspec 2 to fix this except reimplementing the support for
produces and fails to be matchers. (Rspec 3 has composable matchers that
may make this simpler).

A ticket has been logged about further improvements to the two support
functions (produces, and fails).
(PUP-3117) Complete the implementation of resource expression

This completes the implenentation of the Resource Expression.

* The LHS must now be a QualifiedName (i.e. file, notify), or
  a QualifiedReference (i.e. File, Notify), or an access expression
  with a left QualifiedReference (i.e. Resource[file]), or literal
  'class'

* The result of the LHS must be a CatalogEntry type, and it may not
  be detailed to title level.

* The * => syntax can be used to to unfold a hash. It may be used
  once per titled resource body. Attribute names must be unique across
  the attributes set with name => expr, and those set with * => hash.
(maint) Remove unused issue codes APPEND_FAILED, and DELETE_FAILED
(maint) Fix faulty issue ILLEGAL_NUMERIC_PARAMETER and validation

There was a typo in the message that referenced a non existing variable.
This was undetected because there was no test to cover this.

When testing the expected behavior, it was found that the validation
was not correct as it allowed parameters to have hexadecimal names, but
not octal names. Now all numeric parameter names are disallowed (they
cannot be used or addressed anyway).
(maint) Fix bad comment for issue ILLEGAL_VARIABLE_EXPRESSION
Merge pull request #3024 from hlindberg/PUP-3117_resource-expression-splat-rocket-alt

(PUP-3117) Complete the Resource Expression implementation