Update libvtd: get TS.ClearFiles()
Enable updating list of files on the fly

For example,
  :Glaive vtd files+=`expand('~/Google Drive/newfile.vtd')`
This will add "~/Google Drive/newfile.vtd" to the system.

  :Glaive vtd files=`[]`
would clear the system.
Enable on-the-fly changes of 'contexts' flag