atomic lint dense linear algebra
CMake/*:
- made changes to build system to properly find the intel MKL on x86_64 chips.
- upgraded to eigen 3.4.0
Clang-tidy/*:
- added more explanations of excluded (i.e. not useful for our purposes) checks and changes for configuration
LectureCodes/DenseLinearAlgebra/*:
- removed "using namespace", since it clutters the translation unit
- introduced const wherever possible
- removed duplicate type specifications (used auto in this case)
- integer type hygiene (prevented comparison of different signedness and narrowing conversion)
- sorted includes by name
- avoided pointer arithmetic, replaced with vectors/arrays/spans
- avoided multiple return or exit in main, used proper branching and exit codes instead
- modernized headers
- modernized function declaration