cleanup gemfile, move guard gems to guard group

.travis.yml

@@ -15,6 +15,7 @@ matrix:
     - rvm: ruby-head
 
 before_install: gem update bundler
+bundler_args: --without guard -j 3
 
 sudo: false
 cache: bundler

Gemfile

@@ -6,9 +6,12 @@ group :test do
   gem "tins", "~> 1.6.0" # 1.7 requires ruby 2.0
   gem "pry-nav"
   gem "rack"
-  gem "guard-rspec", platforms: [:ruby_19, :ruby_20, :ruby_21, :ruby_22]
-  gem "rspec", ">= 3.1"
-  gem "growl"
-  gem "rb-fsevent"
+  gem "rspec"
   gem "coveralls", platforms: [:ruby_19, :ruby_20, :ruby_21, :ruby_22]
 end
+
+group :guard do
+  gem "guard-rspec", platforms: [:ruby_19, :ruby_20, :ruby_21, :ruby_22]
+  gem "growl"
+  gem "rb-fsevent"
+end