feat: font generation from ttf (#882)

* chore: add file variant of json fonts

* chore: add stb dependency

* feat: generate fonts from ttf files

* chore: add option to add yOffset to file font

* chore: dynamically adjust generated font bitmap size

* fix: printable characters should respect ISO-8859-1 control characters

* chore: do not write missing glyphs into the bitmap

* chore: remove test texture conversion

* chore: adjust font compiler for iw3,iw4,iw5,t4,t5

* chore: add possibility to fill color channels when converting

* fix: games other than t6 use rgba for fonts

* fix: make sure no mipmaps are set on loaddef

* fix: t4 and iw3 use dimensions in image loaddef

* chore: also include optional glyphs in fonts

.gitmodules

@@ -22,3 +22,6 @@
 [submodule "thirdparty/webwindowed"]
 	path = thirdparty/webwindowed
 	url = https://github.com/Laupetin/webwindowed.git
+[submodule "thirdparty/stb"]
+	path = thirdparty/stb
+	url = https://github.com/nothings/stb.git