Specifically:

- In parser, check that all exports are defined.
- Move JSModule allocation from parser to scope resolution.
- Move JSModule linking from full codegen to scope resolution.
- Implement module accessors for exported value members.
- Allocate module contexts statically along with JSModules
  (to allow static linking), but chain them when module literal is evaluated.
- Make module contexts' extension slot refer to resp. JSModule
  (makes modules' ScopeInfo accessible from context).
- Some other tweaks to context handling in general.
- Make any code containing module literals (and thus embedding
  static references to JSModules) non-cacheable.

This enables accessing module instance objects as expected.
Import declarations are a separate feature and do not work yet.

R=mstarzinger@chromium.org
BUG=v8:1569
TEST=

Review URL: https://chromiumcodereview.appspot.com/10690043

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12010 ce2b1a6d-e550-0410-aec6-3dcde31c8c00