ok merge

Merge branch 'master' of https://github.com/cexbrayat/linkit
Optional language flag (fr/us) displayed everywhere. Input required when editing session.
Credits for language flag icons in humans.txt
Merge pull request #168 from clacote/talk-flag-lang

Optional language flag (fr/us) displayed everywhere. Input required when editing session.
Merge pull request #167 from fdepierre/master

Change agenda to improve English track
Expose valid sessions as JSON : /api/sessions
Expose interests as JSON : /api/interests
Expose lightning talks as JSON : /api/lightningtalks
Expose staff, sponsors, members as JSON : /api/staff, /api/members, /api/sponsors
Tests of JSON API
moved for cleaning (Git case-insensitive)
Merge pull request #169 from clacote/api-json

Expose JSON Api (read-only) for mobile apps
Fixed mailing queries : failed speakers and speakers now uses current event only
Merge pull request #170 from clacote/fix-mailing-event

Fixed mailing queries : failed speakers and speakers now uses current ev...
Fixed mailing queries : failed speakers and speakers now uses current event only
JSON API : by id
Merge pull request #171 from clacote/api-json

Api json : by id
JSONP support in API
Cleaned Javadoc
Merge pull request #172 from clacote/jsonp

JSONP support in API