Improved error checking when defining classes and using %template.

1. When a template is instantiated via %template and uses the unary scope
operator ::, an error occurs if the instantiation is attempted within a
namespace that does not enclose the instantiated template.
For example, the following will now error as ::test::max is not enclosed within test1:

Error: '::test::max' resolves to 'test::max' and was incorrectly instantiated in
scope 'test1' instead of within scope 'test'.
  namespace test1 {
    %template(maxchar) ::test::max<char>;
  }

2. SWIG previously failed to always detect a template did not exist when using
%template. In particular when instantiating a global template incorrectly within
namespace. The code below now correctly emits an error:

Error: Template 'test5::GlobalVector' undefined.
  namespace test5 {
  }
  template<typename T> struct GlobalVector {};
  %template(GVI) test5::GlobalVector<int>;

3. Also error out if an attempt is made to define a class using the unary scope
operator ::. The following is not legal C++ and now results in an error:

Error: Using the unary scope operator :: in class definition '::Space2::B' is invalid.
  namespace Space2 {
    struct B;
  }
  struct ::Space2::B {};

1 files changed, 0 insertions, 2 deletions

diff --git a/Examples/test-suite/errors/cpp_nested_template.stderr b/Examples/test-suite/errors/cpp_nested_template.stderr
index 363a260f6..5b107cad4 100644
--- a/Examples/test-suite/errors/cpp_nested_template.stderr
+++ b/Examples/test-suite/errors/cpp_nested_template.stderr
@@ -1,4 +1,2 @@
 cpp_nested_template.i:9: Error: 'Temply' resolves to '::Temply' and was incorrectly instantiated in scope 'A' instead of within scope ''.
-cpp_nested_template.i:9: Warning 324: Named nested template instantiations not supported. Processing as if no name was given to %template().
 cpp_nested_template.i:18: Error: 'Temply' resolves to '::Temply' and was incorrectly instantiated in scope 'B' instead of within scope ''.
-cpp_nested_template.i:18: Warning 324: Named nested template instantiations not supported. Processing as if no name was given to %template().