Switched to using entry_points

[iiSeymour]

Patch for #15

[iiSeymour]

Another couple of commits that fixed the examples (forgot to created a new branch).

• The DropBox URL's redirect so added -L so that curl follows.
• hist -d expected the relative file ./data/exp.txt to exist
  • now exits gracefully if it doesn't
  • made example/*sh use paths relative to the scripts location not the location in which the script get run from.
• The last two examples in sample.sh are broke so just commented them out for now.