Let Endpoint methods take options hash only
Rename settings to parameter its purpose

* Xway::Settings => Xway::Parameter
* Xway.settings => Xway.parameter
Setup coding rules when to use Xway.parameter
Let Api use Xway.parameter[:app] to setup requests
Finish basic create call to work with real appway

 - add app.name param
 - add app.manifest param
 - add Request#http_options
 - add example manifest file for github.com/threez/appway-example
 - stub out request for api spec
Replace Api#method_missing with #request
remove X
Refactor whole Api implementation

 - only mock classes heavily depending on external implementation in api specs (endpoints + http)
 - extract Xway::Api::Request::Body class
 - add debug flag to Http class
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