* Refactor deleteUnusedChannels in FxMixerView

* Comments + style fix

Co-authored-by: Veratil <veratil@gmail.com>, formatting, suggestions on which lines to comment.

Co-authored-by: Kevin Zander <veratil@gmail.com>

* Update weird deleteChannel loop

* Use vector instead of array

Co-authored-by: Dominic Clark <mrdomclark@gmail.com>

Co-authored-by: Kevin Zander <veratil@gmail.com>
Co-authored-by: Dominic Clark <mrdomclark@gmail.com>

* Limit note length to quantization value

Draging a note to it's minimum value of 1 will add this new length to
the note if you later choose to stretch it which will not be clearly
visible in the Piano Roll unless you zoom in a bit. Limit the note
length to the quantization value and use <Alt> key to override and set
a smaller value.

* Update src/gui/editors/PianoRoll.cpp

Co-authored-by: Spekular <Spekular@users.noreply.github.com>

* Remember min note length if shorter than quantization()

* Find note length modulo quantization, pick smallest from selected notes

* Comment on and improve m_minResizeLen calculation

Co-authored-by: Oskar Wallgren <oskar.wallgren13@gmail.com>

* Removed the excessive margin in instruments' GUI (#5129)

* Reduced the font size for "master pitch" label.
* Reduced the layout spacing for MIDI Input and MIDI Output groups
* Shortened labels, so that the LcdSpinBoxes are spaced evenly

* Added translator's comments

* Whitespace fix

This makes AudioDevice::resample return the actual number of generated samples.