This is used subsequently to simplify the conversion generation, so each
package can declare what peer-packages it uses, and have those imported
dynamically, rather than having one mega list of packages to import and not
really being clear why, for any given list item.
Remove some indentation from file generation for specific languages,
allow SnippetWriter's io.Writer to be accessed, and add Path to
types.Name for languages where Package and Path can be disjoint.
* Add support for pointers, map keys, more builtins, Alias types
* Support for packages & imports
* Add helper functions to types
* change generation interface
* fix naming/ordering
* SnippetWriter for templates
* Naming systems
* Use the standard packages for import resolution
* Documentation
