Implemented conference views, still incomplete
draft: relating talks with conferences
Created talks are now associated to their conference automatically, allows the creation of several talks in series ("thanks" view)
Using conference/id/talks now returns a conference's talk list
Talk details are now accessed through 'conference/conference_id/talks/talk_id' instead of 'talks/talk_id'
Removed base 'talks/' routes
Updated migration schemas and added 'location' field to both conferences and talks
Fixed minor typo
Added seed with several conferences and talks
Adjusted condition checks
Added localization files
Available locales MUST be added to the corresponding config/environments/*.rb files through config.i18n.available_locales
Merge pull request #7 from RMed/develop

Fixed automatic localization
Added missing strings in thanks views
Minor adjustements to locales, updated seeds to that one of the conferences has voting process enabled
Fixed 'mailto' links in thanks views
Added location links in the upper part of the page (still mising for the voting page)
Removed link for current page
Added more missing locales
Merge remote-tracking branch 'upstream/develop' into upmerge

Conflicts:
	config/locales/en.yml
	config/locales/es.yml