2016-06-25: "Brexit": Normalize and stop legacy support.

• Less rigorous support for python-2 < 2.7 and python-3 < 3.3.
• Package normalizations and :pep:503 updates:
  • Package names are normalized: convert all characters to lower-case
    and replace any of [-_.] with a dash('-').
  • The simple index only lists normalized package names.
  • Any request for a non-normalized package name is redirected to
    the normalized name.
  • URLs are redirected unless they end in '/' (expect packages themselves).
  • (thanks to @dpkp, #38, #139, #140)
• Added pip search support.
  • (thanks to @blade2005, #80, #114)
• FIX startup regressions for other WSGI-servers, introduced by previous v1.1.10.
  • (thanks to @virtuald, @Oneplus, @michaelkuty, @harcher81, @8u1a,
    #117, #122, #124/#127/#128)
• FIX over-writing of packages even when without --overwrite flag.
  • (thanks to @blade2005, #113)
• Fixes for paste, gunicorn and other WSGI servers.
  • (thanks to @corywright, @virtuald, @montefra, #112, #118, #119)
• Updates and fixes needed due to changes in dependent libraries.
  • (thanks @dpkp, #120/#121, #129, #141/#142)
• Add cache for speeding up GPG signatures.
  • sthanks to @virtuald, #116)
• Other minor fixes and improvements.
  • (thanks to @bibby, @Oneplus, @8u1a, #129, #131)
• TravisCI-test against python-3.5.
  • (#107, #108, #110)
• docs:
  • Provide samples for Automated Startup (systemd & hypervisor).
    (thanks to @ssbarnea, #137, #146)
  • Add usage instructions for related project pypi-uploader.
    (thanks to @ssbarnea & @bibby, #147)
  • doc: Provide sample-code to authenticate using /etc/passwds file
    via pam modules in Unix.
    • (thanks to @blade2005, #149, #151-#153)
  • Improved API usage instructions.
  • Detailed changes recorded in Github's milestone 1.2.0 <https://github.com/pypiserver/pypiserver/milestones/M1.2.0>_.
• TODO:
  • Move validations from main() --> core.configure().
  • Use docopt.
  • Privatize pypiserver.core --> pypiserver._core.
  • Finish rework of app+bottle config & startup that began on 1.1.9.
  • Add logging-conf yaml-file and read it if found