FluidCompose 0.4 alpha release

Changelog

- item lock (disable depth changing for background items with a shortcut).
- UI translations to the Ukrainian language.
- stay-on-top implementation for using FluidCompose as a reference manager (same as PureRef).
- semi-random names generator for exported images.
- aspect ratio options for exported images.
- text elements on double click on the scene.
- context-coloured borders remain consistent with the sidebar.
- colour filter for images inside the editor.
- different lasso modes are activated with a shortcut.
- export was moved to side tools.
- export as .jpg file

Fixes

- correct position for gradient-choosing dots.
- solid coloured background export.
- all warnings were fixed.
- text rotation wasn't saved.

Sidebars  

Pink - text editor.  
Yellow - image editor.  
Green - export.  
Blue - composition editor.  

Known issues
- exported only with predefined names. [bug]
- on paste, the whole image is pasted (without lasso regions). [future feature]
- typo in the opacity filter name. [bug]
- opacity sliders do not always show the actual correct value. [platform-specific]