add util.GetNodeVersion and create .gnvmrc set globalversion
move nodehandle.getNodeVersion to util.GetNodeVersion
add gnvm config INIT logic
add util.GetLatestVersion()
move nodehandle.GetLatestVersion() to util.GetLatestVersion()
Fixbug of gnvm config INIT parameter logic
Fixbug of gnvm config INIT parameter logic
modify copywritting.
Merge branch 'feature/gnvm-config-support' into develop