Fix Window ScreenShot (MathewSachin#314)

- Removed ScreenShot Transforms in favour of Image Editor
  Corresponding Settings, Localisations and UI removed.


- Fix Window Rectangle finding code.
- New option in ScreenShot settings: `Window ScreenShot Transparency` to specify whether window screenshots should be transparent.
- Mouse Cursor included in Window ScreenShot only if within window bounds.
- Capture Window Transparent region inflation reduced from 100px to 20px.
- Refactor code into a `WindowScreenShotBackdrop` class.


- Other Fixes:
  - `CustomSize` used instead of `CustomUrl` on `FFmpegPage`
  - `MouseRightClickColor` used instead of `MouseMiddleClickColor` on `MouseOverlayPage`

Fix Cmdline Region capture

UI Redesign (MathewSachin#253)

List view for selecting video source and encoder.
Window Picker and Screen Picker used instead of dropdowns.
Quality, FPS options shown only when relevant.
and more...

Fix Audio (previous commit had faults)

Fix Audio distortion using MixerLimit flag

Point Documentation to New Website

Not deleting the docs folder to prevent broken links

Update Changelog

Update Changelog

Dispose Bitmaps in ScreenProvider (fixes MathewSachin#141)

Fix build.cake Setup