Generated Gemfile missing necessary line breaks

[chrisvogt]

I keep running into the newline issue mentioned in #143.

This PR corrects the Gemfile template by breaking apart the conditionals, giving each its own line.

Generated Gemfile

Before (current):

source "http://rubygems.org"

gem 'jekyll', '~> 2.3.0'gem 'redcarpet'gem 'sass', '~> 3.4.3'

After:

source "http://rubygems.org"

gem 'jekyll', '~> 2.3.0'
gem 'redcarpet'
gem 'sass', '~> 3.4.3'

[prestancedesign]

+1