Update docker-library images

- `docker-dev`: `1.3.2`
- `golang`: support for Go 1.4 "Custom Import Paths" (docker-library/golang#32)
- `python`: smaller and `--enable-shared` (docker-library/python#23); slim variants (docker-library/python#24)
- `tomcat`: jre8 versions (docker-library/tomcat#5)