Peter M. Groen / openbr

generalized CLOSEDBR_DIR to BR_THIRDPARTY_DIR

For consistency with other supported compilers, enable a warning about
unused parameters at warning level 3 in visual studio.

By default this warning is at level 4, but using level 4 isn't really
feasible since a ton of warnings are generated for Qt header files.

RandomLib provides a variety of rng functions