The most important changes:
* Rename "Profiles" to "Render Presets"
* Separate presets view and model code better
* Extend preset editor to have all important options in the UI instead of needing to write the properties by hand
* Add a batch render mode using guides as separator
* Re-implement "Stem audio" export under new name "Separate file for each track"
* Other UI improvements and face lifting

Fixes #211
Related to #444

BUG: 415610
FIXED-IN: 22.04.0

Add option to seek to clip on add effect (enabled by default, can be disabled from Kdenlive Settings > timeline)
Fixes #703 #1218

Add option in timeline preview menu to render preview using original clips, not proxies (disabled by default)
Fixes #1332

This adds a new python interface class that is now used by text to speech and otioconvertions. One of the main goals is to offer dependency management for otio in a the same why it is already possible for text to speech.

Other achievements are

* reduce duplicated code
* make it easier to add more python based features in the future
* more detailed error messages in some situations

BUG: 423083

Related to #1273

Fixes #949

Kdenlive display settings: allow to define on which physical monitor the fullscreen monitor view will show up

This is usefull for clips with transparency like title clips, png
images, etc.

Change the color from the clip monitor's hamburger menu (entry
"Background Color")

Fixes #1195

Fixes #1179

Fixes #1106

Add option to lock/unlock guides. Unlocked guides will move along when using spacer tool or adding/removing space

Can be enabled in Settings.

BUG: 353051
Related to #973  and #1009

Pistos Pi authored Jan 05, 2021 and Jean-Baptiste Mardelle committed Jan 06, 2021

Allow users to choose between:

- scroll wheel in timeline scrolls horizontally, Shift + scroll wheel scrolls vertically
- scroll wheel in timeline scrolls vertically, Shift + scroll wheel scrolls horizontally

Related to #886

Zoom effect keyframe on CTRL + wheel, add option to move selected keyframe to current cursor position

Don't create the kdenlive-renderqueue folder if not necessary, and delete it if no script is stored.
Fixes #812

Related to #798

Rotoscoping: add Auto keyframe button in monitor toolbar to automatically add a keyframe when moving a point

Related to #651