This program reads the content of an OPF file used in Calibre.
It may then modify that content and tell Calibre to update it.
Essentially the program seeks to put all Author names into the Tags (subject fields), for the related ebook.
If multiple authors are found, then the Author (creator fields) may also be adjusted. With five or more author names listed the process is automatic, but less than that it is queried.
The adjustment, is generally a single author called 'Various' being created for the sole Author (creator field), and all the other author names relocated to Tags (subject fields) and also to the start of the Comments (comment field).
It is recommended that any existing Tags are not kept, so that you can gain the utmost from the new Author Tags.
NOTE - Tags are often abused by authors or publishers, so their usefulness is problematic or debatable anyway."
 January 2020 - 'Authors To TAGs v1.0' created by TheSaint.

(v1.1) Enabled command-line usage.

(v1.2) Additional checking for Calibre running. Further improvements for re-doing/fixing 'Various', including some HTML replacements for the Inputbox box other authors query.

(v1.3) Further improvements for author name detection, extraction and fixing, including L,F to FL.

(v1.4) Implemented my own type of InputBox (a GUI really) with many more helpful features and no text limitations, to be used when dealing with 'Other Authors'. This is a kind of Bugfix for the InputBox character count limit.

(v1.5) Added more helpful buttons for 'Other Authors' and improved other aspects for them.

(v1.6) Changed the options for TAGS, so that they can now also be relocated to the Comments (Description) field. Bugfixes, improvements.

(v1.7) The currently set default calibre library path is now detected for browsing. Improved handling and bugfixes for HTML elements. The 'Open Folder' button now has right-click options.

(v1.8) Added an ampersand '&' button, which also has CTRL and SHIFT options. CTRL = Undo last change. SHIFT = Search for ' by ' in text from cursor position and select. Vastly improved HTML removal.

(v1.9) Ebooks that are skipped are now also recorded in a Skipped.txt file, and the advise dialog now auto closes after 9 seconds if processing via command-line (for batch continuation support).
