Some nice new features and some bugfixes.

• Added a checkbox in `DISK OP` settings which enable saving and loading of `.zpt metadata` alongside the saved module. The sidecar file stores session specific metadata like pattern names and channel names. In the future more cross-session metadata will be stored there. This feature does not break the .mod format and is entirely optional.
• Added a `BOSS SCREEN` so you can safely track awesome music while at work :D Switch to it using `Ctrl+F11`.
• Added a `SEARCH` tab to the `Disk Op` screen where you can search `modarchive.org` and `AMP` for modules by name or artist.
  
• Added a `BEAT DETECT` function for `BEAT SYNC` which try to detect the BPM/FXX for current sample and set `BEAT SYNC` values accordingly. Note: Detection is based on the last played note.
• Added CTRL+Left-click, Right-clicks etc to the help screens.
• Rearranged the first `DISK OP` page a little bit to fit a `FILTER` field in which let you add a custom filter for the file listing. I also removed the `PACK` button since it wasn't implemented.
• Reworked the `POS-ED` into a fullscreen modal screen. Refer to `Shift+F1` help for keybindings.
• Rewrote the `MOD2WAV` into a new `STEM2WAV` function which let you render instrument stems to separate .WAV files. These can be loaded into a DAW for mixing and mastering.
• In `VIBE MODE` the song title is shown first in the text pager and scroll text.
• Fixed ranged selection processing for `BACKWD`, `X-FADE` and `FIX DC` which broke after I added long sample support.
• Fixed a row order rendering bug which broke contiuous flow in `Vibe Mode`.