Removed no longer supported functionality (friends, event, events, pa…

…stevents, tagged, post, postlink, postvideo) and rewrote direct API access examples to reflect what is still possible

Format JSON results when 'api' returns a collection

Customizable host name for receiving auth code during login (such as …

…on a remote machine)

Eliminated no longer necessary steps from setup instructions

Updated setup instructions to work with recent backend change to OAut…

…h redirect URI expectations

Facebook now requires that the OAuth redirect URI be explicitly specified in the facebook app settings.

See: https://www.nextscripts.com/instructions/facebook-social-networks-auto-poster-setup-installation/october-2017-facebook-changes/

Also improved user interaction surrounding the login procedure and handling of the access token.

Updated to Graph API v2.10

Post to pages and groups via the --to flag; closes #5,#10,#12

Better documentation and friendlier setup instructions

Don't trap PIPE signal if it's not available on the host system; closes 

#14

Inspiration from:
  rouge-ruby/rouge@c46f01b

Also omitting "SIG" prefix, as the Ruby documentation endorses:
  http://ruby-doc.org/core-2.4.1/Signal.html#method-c-trap

Extract specific values from API response via 'api --get'