add hooks for onConnection, onLoad and Transaction.query

create test for example1.js
start testing multi-transaction (test failing when run with something
else...)
parametrized schema with public schema by default
add beforeEnd hook, onConnection test

add a context for debugging
change how failure is handled on BEGIN
consistently return client
call pg.end()
update to new client.poolCount
change flow to execute a chain within the then following a connect
add initialization test
make sure config is not shared between require'rs
trap cases where nothing is returned