Remove unused scripts/pipbot directory

The intention was that this would be used to store pipbot
configurations, but this isn't used since we're storing configuration
files in ~/.local/etc/pipbot/
pipbot: Use a singl ~/.pipbot/config.json file

Previously, we had two JSON configuration files:

    ~/.local/etc/pipbot/build.json
    ~/.local/etc/pipbot/targets.json

... with more on the way, as the project expanded. This isn't a very
smart way of doing things, when we could just have a single centralised
configuration.

Issue #195.
pipbot: Ensure double lines between defs
pipbot: Rename file path constants
pipbot: Refactor build command

... to use the standard print_usage_and_return() routine.
pipbot: Refactor deploy command

... to use the standard print_usage_and_return() routine.
pipbot: Refactor undeploy command

... to use the standard print_usage_and_return() routine.
pipbot: Get home directory path using expanduser

This means that we don't need to hardcode directory paths. So:

   "/home/chris/foo"

becomes:

   expanduser("~/foo")

Issue #195.
pipbot: Define project root in config file

This replaces the hardcoded path to the project root:

  project_root = expanduser("~/src/pip-db/")

with a function that looks up the project root within the config.json
file. The project root is set within config.json with the addition of a
"project" element, with contains a "path" attribute:

  "project": {
    "path": "~/src/pip-db/"
  }

Issue #195.
Merge branch 'issue/195'