Use Stream instead of *Serial/TwoWire

for newer arduinos,
- HardwareSerial
- NewSoftSerial
- TwoWire
- Serial_ (USB CDC)
are all subclass of the Stream abstract class.

and this way we automagically supports all transfer method which is
derivered from Stream.
Merge pull request #4 from Palatis/master

Use Stream instead of *Serial/TwoWire; major props to Palatis
Merge branch 'master' of https://github.com/madsci1016/Arduino-EasyTransfer

Conflicts:
	EasyTransfer/EasyTransfer.cpp
	EasyTransfer/EasyTransfer.h
Resolved by replacing "theSerial" with "theStream" and "_serial" with "_stream"