Add title to exercise in factory to match validation

- also removed forgotten print() statements in exercise specs

(Closes #17)

Author: leoselig

spec/factories/exercise.rb

@@ -6,6 +6,8 @@
   end
 
   factory :exercise_with_single_java_main_file, class: 'Exercise' do
+    title 'Some Exercise'
+  	description 'Very descriptive'
     after(:create) do |exercise|
        create(:single_java_main_file, exercise: exercise)
      end

spec/models/exercise_spec.rb

@@ -15,7 +15,6 @@
         }
 
         it 'has single <p:description> tag which contains description' do
-          print(xml)
           descriptions = xml.xpath('p:task/p:description/text()')
           expect(descriptions.size()).to be 1
           expect(descriptions[0].content).to eq 'Very descriptive'
@@ -70,7 +69,6 @@
       }
 
       it 'has single /p:files/p:file tag' do
-        print(xml)
         files = xml.xpath('p:task/p:files/p:file')
         expect(files.size()).to be 1
       end