Add more types to ASTNodeKind. Refactor common instantiation code.

Summary:
Add support for CXXCtorInitializer and TemplateArgument types to ASTNodeKind.
This change is to support more matchers from clang/ASTMatchers/ASTMatchers.h in the dynamic layer (clang/ASTMatchers/Dynamic).

Reviewers: klimek

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1143

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186422 91177308-0d34-0410-b5e6-96231b3b80d8