v0.5.3

• you can now open a chart through commandline arguments !
  • pass in --beat (n) to start a specific beat, and --checkpoint (i) to start at a specific checkpoint (1-indexed)
  • this means you can assign .xdrv files to open in trackmaker.exe or your platform's equivalent
    • trackmaker.exe still uses love2d's default icon which i realllyyy want to change but i don't think i could design a logo on my own
• snap scrollwheel to quants
• autosave, .old files as backups
• slight fixes to try and prevent note loss during .xdrv serialization

full changes: v0.5.2...v0.5.3