adds configuration for shortcut FactoryGirl methods to spec_helper.rb
adds capybara, launchy and byebug gems for integration testing and debugging
updates validation in user model for users#update behaviour
reverts spec_helper to not use FactoryGirl shortcut methods; updates user-spec accordingly
removes commented-out-debugger from Gemfile
replaces implicit with explicit error expectations in user model spec
removes debugging tool from public repo for good
Merge pull request #53 from RaimundSchramm/change/behaviour-of-update-user

Validate password only if changed. Fixes #50