Synth-mapping-helper

Also includes some other fixes and an example how to use the api to change bpm on a whole map

* `--offset-random` now accepts multiple ranges, which allow for example placement to the left and right of the play space
* Added `--rotate-random=[MIN:]MAX`, which does random rotation and also supports multiple ranges (eg. `--rotate-random=0:0 --rotate-random=90` if you want randomize between horizontal and vertical)

See `randomized_decorative_wallart.txt` for an example

* Flip X axis such that it can be interpreted as top-down view
* Increase default acceleration scale
* Add plain note count to heatmap

Adds a command to quickly make parallel rails. Check out the new `parallels.txt` helper file!

Also adds some other helper files (three autostack variants & making notestacks from rails).

See https://github.com/adosikas/synth_mapping_helper/wiki/Companion#heatmap-tab

New features:
* `--mirror-left` causes most operations to be mirrored for the left hand, including inverse offset/rotation and spiral/spike directions
* `--stack-duration=<beats>` / `--stack-duration=<seconds>s` as alternative to `--stack-count=<num>` that automatically calculates the number of stacks to fill the duration
* `--wall-rotate=<angle>`, equivalent to `--rotate=<angle> --relative -f walls`, but can be used in parallel to absolute rotation during stacking
* `--autostack` (defaults to OFFSET) / `--autostack=<mode>` with `OFFSET`, `SPIRAL`, `OUTSET` and `SCALE` modes, to automatically determine offset/rotation from two placed objects, and continue the pattern
* OFFSET uses naive xy offset, generating strictly linear stacks
* SPIRAL automatically determines a pivot point and rotation amount and generates strictly spiral-shaped stacks
* OUTSET is based on rotation and distance from center/pivot, generating cylinder or cones
* SCALE is based on relative movement, generating exponential funnels