v0.4.4

• [fltk] allow to regenere9ate certificate/key pair and soft restart
• [core] reduce memory consumption to ~30%
• [core] do not consume CPU when idle
• [core] govern file system operations (scan, read, write, delete etc.) from
  control thread
• [core, bugfix] use system/default ssl root CAs to connect to syncthing infrastructure
  (might require to delete configuration from previous installation).
• [fltk, bugfix] fogetting to insert deleted folder into pending list