Modified some categories' name
Modified some categories' name

To keep the consistency with name conventions of the web page.

takahirom/droidkaigi2016,shaunkawano/droidkaigi2016,cafedeaqua/droidkaigi2016,cafedeaqua/droidkaigi2016,sys1yagi/droidkaigi2016,shaunkawano/droidkaigi2016,konifar/droidkaigi2016,takahirom/droidkaigi2016,zaki50/droidkaigi2016,PriteshJain/rubyconfindia2016,PriteshJain/rubyconfindia2016,konifar/droidkaigi2016,sys1yagi/droidkaigi2016,konifar/conference-sched,operando/droidkaigi2016,cutmail/droidkaigi2016,zaki50/droidkaigi2016,operando/droidkaigi2016,cutmail/droidkaigi2016,konifar/conference-sched