Fix updatecheck; Update .travis.yml

Several improvements @tomrhollis

Several changes for v1.3

- Added plugin-system
- Added scheduled backups (enabled by default)
- Added backup restore functionality (--restore flag)
- Added server watchdog @bennydiamond
- Added setting low-priority of render-processes @bennydiamond
- Added timeout for UpdateChecker HTTP-requests
- Several fixes & optimizations @tomrhollis
- Fix application exit on stop command

Enable hot-backups on Windows

- Fixed issue where the application would exit when "PreExec" or "Pos…

…tExec" commands got executed on Windows

- Fixed issue where the queried file-list output would not get suppressed on Bedrock v1.16
- Added option "OnActivityOnly" to only take backups on player activity
- Added option "StopBdsOnException" to shut down BDS if vellum should crash unexpectedly due to an unhandled exception
- Added "updatecheck" command to manually fetch the latest BDS & vellum versions

- Renamed project to "vellum"

- Bedrock server v1.16 now supported
- Optimized configuration structure
- Fixed a bug where always one backup more than the specified "BackupsToKeep" threshold would be kept
- Fixed an issue where the tool would not continue to proceed to perform a backup if BDS crashed on shutdown while "StopBeforeBackup" was set to "true"
- Fixed an issue where players in-game would not get notified before a server shutdown
- Added CLI option to specifiy configuration-file (-c | --configuration)
- Added overloaded console command to schedule server shutdown ("stop <seconds>")
- Added overloaded console command to reload configuration-file ("reload vellum")
- Added update checker
- Added option "CheckForUpdates"
- Renamed option "TimeBeforeStop" to "NotifyBeforeStop"

Fixed NuGet package deployment

Initial commit