run.sh: Reduce dependency footprint

[TomFrost]

Note: this takes the place of PR #6 -- a duplicate, but from the wrong branch

When deploying a Docker container, it's common to choose a very minimal base image such as one based on alpine, and not only are many of the commands used in run.sh not installed by default in that image, some of them aren't available in the package manager.

This PR:

• removes a lot of functions and variables that are not used
• removes colors and styling from output (tput isn't always available, and Wercker's output doesn't show colors anyway)
• runs the script through /bin/sh instead of /bin/bash, which isn't always available
• allows wget to be used if curl isn't available (this is the case on alpine)

Now, if alpine is being used as the base box, adding this script step in the deploy pipeline will allow this step to run:

- script:
    name: install ecs deployment deps
    code: |
      apk update
      apk add python openssl sudo

Note: theoretically sudo could be removed as well, but since it's very small and available in alpine's package manager, I didn't feel it necessary.

[nhuray]

Thanks @TomFrost for this PR. Seems good to me so I will merge it soon.