Updated math/p5-Math-BigInt to 1.999809
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2017-02-10 v1.999809 pjacklam

* When a new method is added to Math::BigInt or Math::BigFloat, and this new
  method requires a new backend library method, die with a suitable error
  message if the installed backend library does not support this new method.
  The error message says that the method requires a newer version of the
  backend library.

* Fix typos in Math::BigFloat and Math::BigInt.

* Add bfib() and blucas() to Math::BigInt. They return Fibonacci and Lucas
  numbers, respectively. The actual computation of the numbers is done by the
  backend library. Documented both methods in POD. Add test files bfib-mbi.t
  and blucas-mbi.t.

* Add _fib() and _lucas() to Math::BigInt::Lib. They return Fibonacci and
  Lucas numbers, respectively. Document both methods in POD. Add test files
  author-lib-arithmetic-unary-_fib.t and author-lib-arithmetic-unary-_lucas.t.

(mef)