Dev callable2

[skimpax]

Goal of this change is to be able to to plug a more evolved callback than the plain old function pointer.
It extends current usage by allowing using a lambda expression or a callable function object also.
This is very useful when using CronAlarms when the callback parameters are not know at compile time but at runtime only.

eg. to set several relays state, we need the relay pinId and the pinState. They can be read dynamically from a configuration file to set the alarm accordingly.

NOTE:
Your version is 0.1.0 is 2 years old and it lacks the fix regarding the constness (36c5e5b).
It would be appreciated that you deliver your current HEAD in a new version.

[ilhamikivrak]

There is no improvement of performance or feature. What if compiler does not support cpp11?

[skimpax]

Indeed, there is no performance nor feature improvement, it just opens the uses cases of CronAlarms.
This relies on C++11, which is natively available on my dev environment (platform io).
Unfortunately, I am a new comer in Arduino and I do not use constrained AVR chips : I cannot pretend C++11 is available on all platforms targeted by Arduino.
To offer plain old function pointer (legacy) or callable, code must use #define depending on compiler version detected.