add constantExpressions test cases from golang spec
add test case for #989
Merge pull request #990 from bronze1man/pr-test2

add test case for #989
Merge pull request #987 from bronze1man/pr-test1

add constantExpressions test cases from golang spec
Don't create a presentation for broken elements.

Fixes #985
Enable remaining failing tests
Merge pull request #851 from dlsniper/other-tests

Enable remaining failing tests
Updated the return inspection

Fix #989.
But broke others.
Fixed one constant computation test
Fix failing test
Some cleanups and small refactorings with the type system.
Fixed a couple of conversions tests.
Revert a bunch of changes related to constants representability.
Changed the way type resolution works in conversions.
Fix a broken test.
Fixed two broken intentions.
Fixed some basic test cases in error intention
Rebuilt the CheckErrorIntention
Fixed all the convert statement to if intentions
Mark two tests as failing.