v0.5.13-beta1

this release changes: (BETA)

• feature: tabs!
• feature: a global colorpicker
• feature: Semi infinite canvas layout ( thanks @D0V4HKIIN !)
• UI: floating toolbars
• fix: lag when panning in "continuous-vertical" layout
• fix: layers when erasing marker strokes in "split-stroke" mode
• fix: freeze when saving multiple times in succession
• fix: blurry vector images after zooming in