Overhaul and correct main license file.

Rewrite Source Code section to include all information from redundant
LICENSE files.

Modifications to some licenses.

Add Public Domain CC0 license to Open Source Licenses section.

Add DelphiDabbler Exclusive Use License to Proprietary Source Code
section & license branding files and Docs/License.html using it.

License files in new Src/Res/Img/AltBranding directory as Public Domain.

Delete MPL2.0 boilerplate comments from license file: it is no longer
MPL'd

Some other corrections and minor edits.

Author: delphidabbler