Be more DRY when referencing examples and excerpts. E.g.,
```jade
+makeExcerpt('quickstart/ts/app/app.component.ts', 'import',
'app/app.component.ts (import)')
```
can now be just
```jade
+makeExcerpt('app/app.component.ts', 'import')
```
Defined new mixin for examples named `makeProjExample` using this new
scheme.
The original `makeExample` has been left untouched.
Applied new mixins to quickstart.
closes#1420
closes#485 and 479
removal all package.json from _example subdirs and add an example-config.json to each. Update add-example-symlinks to use new fns
updated gitignore, package.json
add tests to QuickStart