v0.48.0

WIP: Initial linux support using SDL (#136)

* Initial linux support using SDL

* fixed link error and gitignore

* fix in working directory initialization (windows side)

* Added README_Linux and fixed a few compilation issues in ubuntu

* Rename main to main_Windows in Tests

* Better default renderering backend selector

* Added backlog terminal output on linux

* added asserts on all missing vulkan function call results

* added portable file dialogs

also small tests update and cleanup

* Added Editor compile target

* linux ci

* linux ci

* cmake update

* cmake update?

* cmake

* Editor_Windows fix

* build test

* make

* build tools?

* update

* ubuntu 20.04

* fix?

* cmake

* build

* build?

* package linux build

* updates, bump version

* backslash to forward slash, eof newlines, add portable-file-dialogs license

* xcopy needs backslash duh; update readme;

* copy fix

* updated readme

* readme update

* updated readme

* updated readme

* fix incorrect file encoding linux

* paint tool fix

* linux: add missing shaders

* packaging update

Co-authored-by: Turánszki János <turanszkij@users.noreply.github.com>
Co-authored-by: Turanszki Janos <turanszkij@gmail.com>