This category contains general questions.
Yes. You should indicate your own address as the billing address, and the shipping address - the address of the person you want to make the gift to.
Currently, we also have development efforts for Linux. Due to its architectural differences from Windows, it is developed completely from scratch, only the algorithmical routing logic will be preserved.
Mobile devices (phones, tablets) are too restricted on what an app can do; in the current state of things it is not possible for an app to extend the functionality of the device's network stack.
OS X is probably an option, only if it would be documented better on its networking stack part. Partly inherited from BSD, it also has the Mach layer, and the documentation is too scarce about it to make any conclusions.