added gem badge to README
added usage and general info to README, resolves #9
added jruby and ruby-head to travis CI build list
created idiomatic gem structure
added bin/gentle.rb
changed version to alpha
get_from_http now returns Hash, resolves #2;
refactoring extract_html_elements
refactoring extract_html_table
refactored long methods and case statements with hashed lambdas
Handled 0 citations issue, fixed #11; bumped gem version to 2.0.0
merged with dev-2.0.0, version now at 2.0.0