Gamma family support

[johnWilshire]

Summary of changes Major changes

• manyglm now supports the gamma family 🎉 with updates to
  • summary functions
  • printing functions
  • anova functions
  • plotting funcitons
  • shape parameter estimation via ML and Method of Moments

Minor changes

• Introduction of unit tests 🎉
  • 7 new tests, mostly for the new gamma family but a couple for the spider data
• Extra whitespace removed 🎉
• .cpp, .h files automatically formatted to clang style LLVM 🎉