- Classroom file watcher was not working as expected because lastModifiedTime of a directory is not updated when a file is changed inside it.
- Added functions watchDir/unwatchDir which is responsible for watching all files and subdirectories changes
- Callback is called once for each detected change
- Changed classroom to check for the last "refresh" made to avoid multiple refreshes without changes
- Changed refresh time to 3s because it is much more comfortable
  - I don't think this would be an issue because checking for lastModifiedTime should be very fast, perhaps even 3s is too much time
- Tested in Windows
last load time must be for each player
Merge pull request #147 from trmfreitas/classroom-autorefresh-windows

Classroom autorefresh not working in windows