Make clear that the master branch is for Bootstrap 2; point users to the bootstrap3 branch.
Make clear that the master branch is for Bootstrap 2; point users to the bootstrap3 branch.

AlexVPopov/select2-bootstrap-css,TMSolution/select2-bootstrap-css,gdseller/select2-bootstrap-css,AlexVPopov/select2-bootstrap-css,t0m/select2-bootstrap-css,ayman-alkom/select2-bootstrap-css,TMSolution/select2-bootstrap-css,t0m/select2-bootstrap-css,emp2web/select2-bootstrap-css,emp2web/select2-bootstrap-css,TMSolution/select2-bootstrap-css,gdseller/select2-bootstrap-css,AlexVPopov/select2-bootstrap-css,gdseller/select2-bootstrap-css,ayman-alkom/select2-bootstrap-css,emp2web/select2-bootstrap-css,t0m/select2-bootstrap-css,ayman-alkom/select2-bootstrap-css