Component name, public interface and doc cleanups

[emuell]

• renamed rust core structs and traits for clarity:

  • Pattern to Rhythm
  • Rhythm to Pattern
  • EventIter to Emitter
  • PulseIterItem to RhythmEvent
  • EventIterItem to EmitterEvent

• cleaned up public Rust interfaces

• updated crate docs accordingly

• renamed Lua API properties and classes:

  • rhythm to pattern
  • pattern to pulse
  • emit to event
  • inputs to parameter

• updated API guides and docs accordingly

fixes #61

[github-actions]

Benchmark for 542b41e

Click to view benchmark

Test	Base	PR	%
Cycle/Generate	48.4±0.57µs	48.7±0.87µs	+0.62%
Cycle/Parse	367.0±7.37µs	354.9±5.61µs	-3.30%
Rust Phrase/Clone	445.1±6.35ns	432.0±5.40ns	-2.94%
Rust Phrase/Create	73.1±1.25µs	72.2±0.68µs	-1.23%
Rust Phrase/Run	630.3±5.54µs	637.1±5.57µs	+1.08%
Rust Phrase/Seek	139.1±256.76µs	140.8±260.16µs	+1.22%
Scripted Phrase/Clone	665.8±5.50ns	650.3±5.61ns	-2.33%
Scripted Phrase/Create	956.4±7.29µs	940.5±14.94µs	-1.66%
Scripted Phrase/Run	1663.3±9.50µs	1661.7±12.30µs	-0.10%
Scripted Phrase/Seek	213.7±432.30µs	215.1±435.58µs	+0.66%

[emuell]

This obviously is a huge change, nearly impossible to diff but I've been quite careful. Also took the chance to update and clear the crate docs a bit.

@unlessgames Implemented as discussed, except I've decided to use event instead of value in the Lua API for the emitter because:

• value works but is super duper generic
• event is how the thing is called in the Rust backend too
• if we add helper modules similar to pulse also for gate and event, event is a better name than value

Such helper libraries could contain functions to create common event patterns (arp and stuff) and common gate impls later on similar to pulse:

return pattern {
  unit = "1/4".
  pulse = pulse.euclidean(3, 8),
  event = event.arp({"c4", "d#4", "g4"}, "up-down")
}

I'll read through the whole thing again and then merge it later today.

Unfortunately the changes can't be made backwards compatible because the old pattern lib definition would clash with the new pattern constructor function - there no such overload resolution in Lua. But I'll create a little script to update existing scripts to the new format to ease the transition. Actually better to get rid of all the old stuff now than never...

[github-actions]

Benchmark for bb9ef2a

Click to view benchmark

Test	Base	PR	%
Cycle/Generate	48.6±0.76µs	48.4±0.52µs	-0.41%
Cycle/Parse	362.6±6.12µs	357.9±5.27µs	-1.30%
Rust Phrase/Clone	439.8±19.09ns	442.4±3.84ns	+0.59%
Rust Phrase/Create	72.5±1.30µs	72.6±0.96µs	+0.14%
Rust Phrase/Run	639.9±1.97µs	630.1±11.14µs	-1.53%
Rust Phrase/Seek	134.4±247.06µs	135.7±250.90µs	+0.97%
Scripted Phrase/Clone	646.2±8.72ns	661.9±13.15ns	+2.43%
Scripted Phrase/Create	946.1±10.04µs	949.9±20.23µs	+0.40%
Scripted Phrase/Run	1661.6±8.54µs	1658.9±22.69µs	-0.16%
Scripted Phrase/Seek	214.5±435.02µs	213.2±432.13µs	-0.61%