AP_HAL and AP_HAL_linux updated +hypelinks added

AP_HAL_Linux updated

AnalogIn and GPIO documentation

I2CDriver documentation

RC I/O documentation

SPIdriver documentation

scheduler doc

semaphores doc

Storage doc

UARTDriver doc

util documentation

Update SUMMARY.md

analogin.cpp

relocated files AP_HAL_Linux
Merge pull request #26 from silvianunez/master

AP_HAL_Linux documentation
AP_HAL_Linux: Review general description and AnalogIn
AP_HAL_Linux: Small updates and improvings.

The docs still need a bit of work.
Minor fix