Remove dead ClickThrough code.

This code was already removed in wix3 branch. Integration apparently did
not delete it in wix4.
Reorganize some preprocessor related code.
Reorganize linker related code.
Remove dead code.
Reorganize some binder related code.
Remove dead code.
Use WixCatalogRow in favor of CatalogInfo.
Adds Table.RowsAs() to get strongly typed rows from a table.
Push the creation of payloads for Bundle catalogs to the compiler.
Extract bundle manifest creation into an ICommand.
Create strongly typed RelatedBundleRow to replace RelatedBundleInfo.
Use strongly typed VariableRow to replace VariableInfo.
Fix typo in comment.
Remove unused code.
Merge pull request #33 from robmen/binder-refactor

Post-Binder Refactor Cleanup