Enhancement: abstract common request arguments

[GoogleCodeExporter]

(all?) request share 'marketplace' and 'merchant-id' arguments but logic for 
those is available in each class file even thought they have a single parent 
class.

For groups of request there might be even more common properties.

Original issue reported on code.google.com by m...@phpkuh.de on 24 Aug 2011 at 7:22

[GoogleCodeExporter]

Conversion to array is shared by all request objects as well.

It is straight forward to reduce Client who holds this logic and put it to the 
abstract base class to be overwritten only on demand, i.e. for special keys.

Original comment by m...@phpkuh.de on 25 Aug 2011 at 5:11

• Added labels: Maintainability