include `no-save` option for test applications
revised build script to include GSL library and several fixes
added build script for heroku and revised others
added test application for GSL
add  PKG_LDFLAGS and PKG_CPPFLAGS to environment
revisions to environment variables
don't delete the VENDOR_DIR ~ impacts multi-buildpack setups
use latest binaries
Merge branch 'master' into development

* master:
  use latest binaries
  don't delete the VENDOR_DIR ~ impacts multi-buildpack setups
  revisions to environment variables
  add  PKG_LDFLAGS and PKG_CPPFLAGS to environment
  added test application for GSL
  added build script for heroku and revised others
  revised build script to include GSL library and several fixes
  include `no-save` option for test applications