AP_Notify: give error msgs on failure to start
HAL_Linux: give error msg on failure to start toneAlarm
HAL_Linux: make rtttl tune and tune repeat flag list static members
instead of initialising them inside constructor
HAL_Linux: make tonealarm generation a passthrough operation
get rid of all delays and while loops(that may turn into infinite loop)
HAL_Linux Scheduler: reduce the delay inside tonealarm thread

Since the tonealarm is now passthrough the delay inside the thread needs to be reduced for precise tune generation
AP_HAL: make toneAlarm_init() return bool
HAL_Linux:create ToneAlarmDriver as a separate class

ToneAlarm is now declared as a separate class instance of which is added as a private member of LinuxUtil
Some minor fixes in this patch include changing return type of tonealarm_init() to bool and use dprintf
AP_Notify: cleanup use of bool from toneAlarm_init()