virtualenv: avoid to reinstall applibs except if requirements changed
virtualenv: avoid to reinstall applibs except if requirements changed

inclement/buildozer,inclement/buildozer,kivy/buildozer,rnixx/buildozer,inclement/buildozer,superalex/buildozer,rnixx/buildozer,rnixx/buildozer,kived/buildozer,bob-the-hamster/buildozer,kivy/buildozer,kivy/buildozer,eHealthAfrica/buildozer,kived/buildozer,rnixx/buildozer,inclement/buildozer,dvenkatsagar/buildozer,techtonik/buildozer,techtonik/buildozer,ehealthafrica-ci/buildozer,kivy/buildozer,cbenhagen/buildozer