Move existing wrapper classes to V2
add wrapper classes for CakePHP 3.x
Correct invalid url check

There is no scheme if the url is invalid - there may still be path and
or other elements
don't force everything to be a string

if the input isn't a string, the dsn or wrapper class has cast it to be
that type - honor the returned type
move aliasing logic

It was weird/awkward to have to write methods using the aliased key name
by moving to __call - methods relate to the key used by the wrapper
remove setters

they aren't used or tested - so right now they are cruft
add doc blocks

and remove some wrapper functions that look to be in the wrong place
consolidate adapter-map logic
consolidate adapter map for v3 wrappers
add doc blocks

and add type correctiosn
remove need to create null getters

use the key map and map the key to false
allow for making keys mandatory
test corrections
add APP_NAME as a global find and replace

fixes #4