Enhance GPIO emulator adding basic functionality for test cases.
Cleanups
Introduce ARDUINO_INLINE_API macro

The ARDUINO_INLINE_API macro is used when defining
Arduino APIs that are compiled as 'static inline'
functions for the real hardware.  However, when
compiling for the emulator, we define the macro as
empty, making the symbol to appear in the emulator
shared library.  However, note that in most cases
they will be mangled C++ names, and must be called
as such from the Python side.
Introduce ARDUINO_INLINE_MEMBER_FUNCTION and ARDUINO_GLOBAL_IMMUTABLE macros
Temp commit adding python-tmp
Fix test case compilation
Align all link-time record sets at 16 bytes boundaries

Also adds linker script support for UDP sockets and CoAP URLs.
Adds initial ellduino support for newer SPI library

Ports SPI library from feature-coap-temp branch

Adds makefile support to properly compile the SPI library.

Work in progress, not clean yet.

Does not compile for STM32F4discovery.
Allow files to be compiled in C mode under the emulator

Adds definitions for memcpy and memset
Fix proper compilation of SPI the library

Now compiles the SPI library properly.

STM32F4discovery compiles but will not work,
due to a number of places not implemented yet.
These are marked with #warning
Enhance test case compilation -- work in progress.
Make tests compile on stm32f4discovery emulator.  Will not work yet.
Cleanups in anticipation of Ethernet driver integration
Fix typos.
Add first version of test_SPI_transfer
Add Register_SPI_SR and Register_SPI_DR to the emulator

This allows us now to track the actual SPI data that goes
through the SPI->DR register, which is accessed indirectly
through a pointer in the spi_transfer code.
Add Robot Framework test cases as a git submodule
Add first version of robot_library and robot_tests

The robot_library is a new interface between the emulator and the Robot Framework.
The robot_tests is a subrepository containing the Robot Framework test cases.
Update robot_tests
Add noAnalogWrite to robot library