tweaks for example code

change typedef to using

remove debugging code

update copyright year

replace asserts by exceptions

cleaner implementation of Moré-Thuente line search algorithm

Merge branch 'master' of https://github.com/yixuan/LBFGSpp

Merge pull request #48 from cho-m/eigen-5.0.0

update Doxygen config file to 1.16.1

Merge branch 'master' of https://github.com/yixuan/LBFGSpp

Merge pull request #46 from TendTo/build/bazel

support building with Eigen3 5.0.0

docs: update README

ci: add .brc folder for continuous integration

docs: add some explanations on how to use bazel in the README