improve install instructions (#475)
improve install instructions (#475)

* improve install instructions

* Update INSTALL.md

* add backticks to install.md

* update install.md

Co-authored-by: Travis Deployment Bot <b0d51b9ff91b623cc42b17c529b7c21c2ab57fb4@travis-ci.org>
Co-authored-by: CGraczyk <e8f8857f68293875e85f00359c24101d77ee245a@users.noreply.github.com>
SCIP-Interfaces/PySCIPOpt,SCIP-Interfaces/PySCIPOpt