changing gigaom4-child/gigaom4-parent to gigaom5

See: https://github.com/GigaOM/gigaom/issues/5325
Merge pull request #30 from zbtirrell/gigaom5-rename

changing gigaom4-child/gigaom4-parent to gigaom5
optimizing images with lossless compression

See: https://github.com/GigaOM/gigaom/issues/5640
Merge pull request #31 from zbtirrell/image-optim

optimizing images with lossless compression
Merge branch 'master' of github.com:GigaOM/go-recurly into freebird-v2