adding tiger_g3 bottle of bash 4.4

bugfix

renaming default gcc to gcc7

pulling in gcc 8

adding tiger_g4e bottle of libpng 1.6.37

adding retry to backblaze upload

adding bottle of libpng 1.6.37

adding bottle of libpng 1.6.37

pulling in libpng and bumping to 1.6.37

adding tiger_g3 bottle of isl 0.22.1

adding an extra call to 'git pull' to build-tap-bottle.sh

adding tiger_g4e bottle of isl 0.22.1

adding leopard_g5 bottle of isl 0.22.1

fixing build-tap-bottle.sh

README