[views] refactor views and add helpers
[controller] refactor exam, exam portion and attachment controller
[factory] exam and exam portion
[helper] translation and link_to* helpers
[spec/request] attachment and exam portion req helpers
[spec/controller] exam portion
Refactor presets
Clean locales
Merge branch 'update_bootstrap_v3' into refactor_presets
[travis] Install postgresql-contrib
[travis] Try to install postgres-9.2 and contrib
Merge pull request #245 from Genshin/refactor_presets

Refactor presets
Merge pull request #243 from Genshin/refactor_bs3_exam_portion

Refactor bs3 exam portion
Merge pull request #246 from Genshin/update_bootstrap_v3

Update bootstrap v3