Added gamma file that uses Bernoulli implementation from gsoc work. The bernoulli using gamma function is currently called using gamma_imp_bernoulli(). Changes need to be further made.
changed tgamma using bernoulli to mimic previous lanczos implementation for z<=-20
Merge branch 'bernoulli-numbers' of https://github.com/boostorg/math into bernoulli-tgamma
Preliminary tests of tgamma(). The undefined_lanczos is hard-coded.
Corrected the Luschny approximation of log(b2n).
Work on tgamma() multiprecision code.
Continued work on tgamma() for multiprecision.
Refactor the multiprecision code of gamma_imp_bernoulli().
Repaired some typos in the multiprecision code in gamma_imp_bernoulli().
Manual merge from branch bernoulli-numbers to branch bernoulli-tgamma.
Continue work on multiprecision tgamma() and lgamma().
Remove some compiler warnings for VC and x64 code.
Preliminary multiprecision tgamma() and lgamma(), phase of lgamma() needs work.
Merge Bernoulli from branch bernoulli-numbers to branch bernoulli-tgamma.
Rework the error handling for multiprecision tgamma() and lgama().
Preliminary multiprecision tgamma() and lgamma() implementations.
Start implementing John's suggestions for multiprecision tgamma() and lgamma().
Finish implementing John's suggestions for multiprecision tgamma() and lgamma().
Merge branch 'bernoulli-numbers' of https://github.com/boostorg/math into bernoulli-tgamma
Rework some comments.