More UI changes

- Left tool options is now on top of the right tool options.
- Brushes have been removed from the right panel, and have instead become a popup that appears when you press one of the brush type buttons, to choose a brush. The indicators will be removed.

Assets/Graphics/pixel.png.import

@@ -1,34 +0,0 @@
-[remap]
-
-importer="texture"
-type="StreamTexture"
-path="res://.import/pixel.png-02d24c392cbedb7afeccdbe493729855.stex"
-metadata={
-"vram_texture": false
-}
-
-[deps]
-
-source_file="res://Assets/Graphics/pixel.png"
-dest_files=[ "res://.import/pixel.png-02d24c392cbedb7afeccdbe493729855.stex" ]
-
-[params]
-
-compress/mode=0
-compress/lossy_quality=0.7
-compress/hdr_mode=0
-compress/bptc_ldr=0
-compress/normal_map=0
-flags/repeat=0
-flags/filter=false
-flags/mipmaps=false
-flags/anisotropic=false
-flags/srgb=2
-process/fix_alpha_border=true
-process/premult_alpha=false
-process/HDR_as_SRGB=false
-process/invert_color=false
-stream=false
-size_limit=0
-detect_3d=true
-svg/scale=1.0