Add highlighting for Pipfile

[remcohaszing]

/~https://github.com/pypa/pipfile

[pyrmont]

@remcohaszing Hello again :) Same request here as in #976. Here are the specs to update:

rouge/spec/lexers/javascript_spec.rb

Lines 19 to 22 in 75676e7

	it 'guesses by filename' do
	assert_guess :filename => 'foo.js'
	assert_guess Rouge::Lexers::JSON, :filename => 'foo.json'
	end

and:

rouge/spec/lexers/toml_spec.rb

Lines 10 to 12 in 75676e7

	it 'guesses by filename' do
	assert_guess :filename => 'foo.toml'
	end

[pyrmont]

@remcohaszing Thank you for helping to make Rouge better :)