Merge pull request #33 from rogerz/efm32

Remove RT-Thread GUI from bsp/efm32
bsp/stm32f10x: remove the last calibration.c

This also provide an example to show how to use calibration feature in
the RTGUI.
remove gui examples

As part of RTGUI, we should also remove gui examples. Copy
demo/examples/* in RT-Thread/RTGUI to examples/gui in RTT When you need
them.
Merge pull request #34 from grissiom/rtgui-cali

bsp/stm32f10x: remove the last calibration.c
Merge pull request #35 from grissiom/remove-gui-examples

remove gui examples
Merge pull request #36 from rogerz/auto-ci

Add building status image in README
building.py: append messed up objs list, use extend to avoid that

The return type of SConscript is a subclass of UserList. We should use
extend to keep the depth of the list is always 1 when concatenate
SConscript return values. Thanks prife for making me realize that this
is really a problem.

Reported-and-Tested-by: prife
Merge pull request #37 from grissiom/fix-building-py

building.py: append messed up objs list, use extend to avoid that