Add a new static method, 'getInstanceCount()'.

This allows you to keep track of the number of instances created.

The release introduces a few more methods.

LedTask::begin(pwm_frequency)
LedTask::updatePwmTask(percentage_duty_cycle)

One blocking method which should not be used in the loop():
LedTask::pulseLedBlk(pulse_count, on_ms, off_ms)

This release improves in two areas.

• documentation
• code quality
  First, Doxygen generates a website from the code itself. Next, GitHub Pages host the final documentation. After that, all code is formatted with 'clang-format' according to LLVM C++ rules. Finally, 'cppcheck' automatically detects flaws, and lastly, all example sketches(s)
  are compiled and uploaded to target microcontrollers.
  It can be excessive work for such a tiny Library, but if the build system lacks the quality for small tasks, it will not be suitable for the next major project. Thus I see this as an exercise for coming libraries.

Release v0.2.0 changes the user interface for the constructor and the begin() function. The interface is with these updates much cleaner and more logical.

The implemented changes are:

• Specify the used Arduino pin# in the constructor and not in the begin() method.
• Remove pin# as one of the parameters for the call to the begin() method.

Initial release.