Refactor common files into super class

[sethladd]

Adding the same boilerplate files into each generator subclass isn't great. Example: I had to add LICENSE to both helloworld and webapp.

Shouldn't Generator take care of that?

[sethladd]

cc @devoncarew for thoughts

[devoncarew]

You can put the contents for files that are going to be identical across projects into src/common.dart, and then reference that content in the generator. We do that for the .gitiignore generated files.

[sethladd]

The contents are in common.dart. It's this line:

_addFile('LICENSE', license);

that is duplicated.

See PR :)

[devoncarew]

Ah, just saw the PR. Makes sense to me. Might be nice to have a subclass of Generator that was private to this library, that did add those more proscriptive things.

[sethladd]

Nice, I'll give that a try.

[sethladd]

Starting now.