hoodie.reset: clean up code and add proper tests and documentation

[gr2m]

the definition of the reset method currently looks like this:

function reset (dbName, CustomPouchDB, state, api, clear, emitter, remoteBaseUrl, remote, ajaxOptions, PouchDB, options) {
// ...
}

it should look more like this

reset (state, options) {
// ...
}

Where state is different from the internal state of the store instance, but having to bind 10 arguments in the right order is not very good to understand / manage.

Maybe there even is a more elegant way to implement the reset in the first place?

Update

also add documentation to README.md

[gr2m]

code gets cleaned up via #153