updt(bootstrap): finalize bootstrap3 update

-- optimized website for IE
-- optimized website for mobile
-- added LGLN reference logo and text
-- redesigned carousel-control to old control
-- add gradient to carousel (without image - CSS3 ;D )

Closes: #CAM-1314, #CAM-1384, #CAM-1204, #CA-253
fix(meetings): add line break between form and btn
updt(Guidlines): update readme and contribution guideline

-- update readme to work with new docpad structure
-- update contribution guidelines to be project specific (e.g.: inline css and so on)
fix(downloads): fix modeler design
fix(downloads): fix modeler design
fix(downloads): fix modeler design
fix(meetings): remove address from overview
fix(links): change deadlinks with working ones
fix(links): change deadlinks with working ones
updt(jobs): change web to frontend developer
fix(users): add whitespace after location and Using
Merge branch 'master' of github.com:camunda/camunda.org
fix(startpage): update tablet version of carousel text