Change connection to take a postgres uri string.
Add Connection onClosed()
Implemented connection pooling
Merge parameter substitution code
Fix postgres pooling, didn't implement parameter substitution
Fix delayed call to expectAsync1()
Implemented simple settings facility.
Revamped tests in order to use the new settings facility.
Updated testing instructions.

Signed-off-by: Paulo Pires <pjpires@gmail.com>
Merge pull request #4 from pires/bleeding_edge

Added Settings class
Update readme
Update readme
Update readme
Update readme
Clean up type constants
Update roadmap.md
Make unittest a dev dependency