Update to include missing #define _BH

[MicahStevens]

Master doesn't include the _BH define. Adding it to the header file so examples compile.

[sleemanj]

_BV is defined by AVR libc itself, are you using a non-avr platform and it doesn't define _BV?

Any non-avr Arduino IDE platform/core/board should probably define it also for compatibility rather than re-define it in each library.

[Doki76]

I have this issue as well when you add your Lib to Arduino Web editor you get the issue that it says _BV not defined.