Add an extra parameter to clone or download a repo
improve code of read-only repo
Update version to 3.1.8.
add server_url param for clone/download repo rpc
add "enable http sync" settings
update "server_url" property for all repos http sync
get server status by ping seahub api
add option "disable verify http sync cert"
fixed server-url property name
Merge branch 'http-sync'

Conflicts:
	CMakeLists.txt
	Info.plist
	seafile-client.pro
	src/seafile-applet.cpp