True/direct (24-bit) color support has landed.

Terminal: Clipboard and DND operations improved.
Terminal: Drag animation for drag-copy operation implemented.
Terminal: WhenClip event added. (Allows client code to inspect/accept/reject pasted/dropped clips.
Terminal: Api doc updated accordingly.

- Sixel graphics support is added to the Terminal package. It is now possible to view sixel images, using the Terminal package.  However, the initial support is only for external viewing. Embedded images are a TODO.

- A basic terminal example with sixel viewer is also added to the package.

- SixelRenderer class and a convenience function: RenderSixelImage is also added to the package. This class and the function can also be used as a stand-alone sixel renderer.

- Alt-key handling is improved.

Terminal: Embedded images support  is added (currently, sixel).
Terminal: Renderer is improved and further optimized.
Terminal: Upp::Display support for image objects are added.
Terminal: LeftAlignedImageDisplay() and RightAlingnedImageDisplay() functions added.

- Terminal: SixelRenderer class is rewritten;
- Terminal: SixelRaster class, a StreamRaster interface for sixel images, is added to the package.
- Terminal: A subset of xterm's window-op reports are implemented.
- Terminal: An I/O synchronization issue with the PtyProcess class that led to artifacts on screen on some setups is fixed.
- Terminal: Inline image support is improved.
- Terminal: Room is made for other inline image protocols.
- Terminal: WhenSixel event is removed in favor of a generic WhenImage event.
- Terminal: Image rendering strategy is changed to cell-level rendering for further flexibility.
- Terminal: An LRU-type shared image data cache is implemented.
- Terminal: Support for Jexer, a modern text user interface (TUI) and windowing system for terminal emulators, is added.
- Terminal: A general purpose data variable is added to the cell structure.
- Terminal: SGR image flag is added to the cell structure.
- Examples: Examples are further simplified.
- Various optimizations and fixes.
- Image gallery is updated.

This example demonstrates the interaction between the Terminal widget and Ultimate++'s Core/SSH package, in a multithreaded environment.
Therefore it also demonstrates the usage and power of U++s own Core/SSH package in a multithreaded GUI environment.

Terminal ctrl is now able to display 24-bit jpeg, gif, bmp, etc. raster formats, using the Jexer Image Protocol and Upp's own StreamRaster interface.

1) It is "8-bit clean". It can be safely deliver images over the network, and with Utf-8.
2) Popular image formats can be decoded much faster than sixels. (Up to 8 to 10 times faster on bigger image files), and usually have a lower bandwidth requirements.
3) Allows 24 bit (true color) images.
4) The wire protocol is very simple.

- Explicit hyperlinks support is added.
- Standard menu  improved and modularized.
- Cell tracking methods are implemented.
- Various fixes and cosmetics.
- Docs are updated accordingly.

ls -l --hyperlink

- Terminal: Rectangle selection is now supported.
- Terminal: Iniline images can now be copied to clipboard or sent to client. (It uses the same mechanism as hyperlinks: CTRL + double click or context menu)
- Terminal: Options menu is implemented. Options menu contains the most relevant options for terminal. 

DnD operations and animations are added for both hyperlinks and inline images. (Activated with CTRL-key modifier)