Remove useless function of spi
Add new typedef to deal with global variable
Replace all PWM Input Capture Value to the new global struct

I will change all global variable to this type step by step.
Unify some naming and declaration
Unify some naming and declaration
Replace all global r/c var to new style structure
Import the FreeRTOS

FIXME:SystemCoreClock is undeclared in function vPortSetupTimerInterrupt()
->path : ./Libraries/FreeRTOS/Source/portable/GCC/ARM_CM4F/port.c
Fix the undefined variable SystemCoreClock

FIXME:implement all the prototype only functions
Add one safety switch, it could let motor be minimum speed

WARNING: This code still have some type casting bug, need to fix it
Move the FreeRTOSConfig.h out of the Libraries directory
Change PWM3~5 counter variable to uint32_t
Because TIM2 CCR is 32bit register, it is more reasonalbe
to use uint32_t
Handl more condition and fix some error
Change param init to be 0 and add prefix to protect gloabal variable
Add all my headers to be dependencies

I add all of my header to be the dependencies of EXECUTABLE.
This action ensure when I change the header file(.h), Makefile
will also rebuild my souce code.
Fix compliation warning
Add a stringization macro for debugging
Implement all system required prototype only functions

*Also disable the configUSE_MALLOC_FAILED_HOOK to avoid implementing the related function
Use macro to define some constant
Handle NO RC signal timeout situation
TODO: Handle the situation: R/C transmitter OFF, but still get CCR value from PWM input
This method only can detect zero PWM input capture
value. Sometimes, the RC receiver keep the last value which
get from RC transmitter. That means MCU still "gets PWM input
capture value". We need to deal with this situation in future.
Merge pull request #16 from poemking/master