fix(getName): get file path using path.join

__dirname + "/../../package.json" would  have /../../ in the middle of the string
Merge branch 'master' of https://github.com/markhuge/hubot-script-installer
Fixed(executable): methods only take one filepath and a callback as the arguments

Edited docs to reflect this change as well.
Merge pull request #8 from tgrrtt/master

Fixed executable and getName uses path.join() closes #5 closes #6