Expand server support section in README
Expand server support section in README

hobarrera/vdirsyncer,mathstuf/vdirsyncer,untitaker/vdirsyncer,untitaker/vdirsyncer,hobarrera/vdirsyncer,untitaker/vdirsyncer,mathstuf/vdirsyncer,credativUK/vdirsyncer,tribut/vdirsyncer,credativUK/vdirsyncer,tribut/vdirsyncer