Merge pull request #30 from yjbanov/master

Emit descriptions as doc comments into the generated code
Adding fixnum library to Streamy temporarily.
Use int64 instead of String.
Merge pull request #31 from alxhub/int64-as-fixnum

Use fixnum's int64 instead of String for int64 values. Also imports the fixnum library into Streamy runtime temporarily, until it's better supported by the Dart team.
Pass addendum data to generator
Merge pull request #32 from alxhub/fix-addendum-generator

Pass addendum data to generator.
Merge pull request #33 from yjbanov/master

Make transformer type parameters more concrete to let users control type...
Merge pull request #34 from yjbanov/master

A bunch of unrelated fixits (see individual commits)