big refactor and some new features over on aiosql

[nackjicholson]

Issue: nackjicholson/aiosql#2
PR: nackjicholson/aiosql#3

Wanted to drop this here to let people in on what I've been adding over on aiosql for my work. I refactored a lot to separate the logic of query loading/parsing from the dynamic creation and binding of methods. I found that adding new features was difficult because these tasks were entangled. By separating them and introducing the QueryDatum as an intermediary my hope is that it will be simpler to add new features and directives to aiosql. One such feature was the record_class directive I added.

Generally I'm working on aiosql first because

1. I depend on it.
2. it has less compatibility restrictions .
3. I need the python3.7 and asyncio features.

I then backport new stuff to anosql if it makes sense because I don't want to abandon our py3.5 and py2.7 friends 😁

I made this issue in order to track getting some of the features into this project as well.

• ^ select one operator
• record_class: MyNamedTuple
• Separation of QueryLoader and Queries method binding.
• A simpler way to provide external driver adapters.
• Changes to exceptions