Disallow variable access in expr of pointer type without dereferencing it first
Added dedicated error and fixed the 'needs dereferencing' error in VariableAccess
Removed resolveAccessInFromType, merged into CoverDecl resolveAccess
Check for needed dereferencing in cover from types as well. Closes #621
Merge pull request #623 from shamanas/master

Make sure we don't access fields without dereference. Closes #621