1) don't ASSERT; use exceptions (which can be caught) instead.
2) clean up LIB_LOGGER so it's only used during sync
3) fix typos in wxLogMessage() calls so they produce output.
4) throw on unrecognized token in loadContent().
5) if clipboard can't be pasted as content then paste as text.
Fixes: lp:1840172
* https://bugs.launchpad.net/kicad/+bug/1840172
Also changes the presentation of the string when the checkbox appears
so that the "Changes will be lost" warning isn't hidden by the turndown.
This last part may require conditional compilation as it's undocumented.
Lastly, regularizes the Unsaved Changes strings between the apps.
A bug in LIB_MANAGER::LibraryExists() prevented a library removed from
the symbol library table from being removed from the tree view. Add the
proper check to SYMBOL_TREE_SYNCHRONIZING_ADAPTER::Sync().
This exposed another issue with synchronization between the library
table editor and the tree view which could lead to orphaned library
modifications and/or a segfault when the currently selected library was
removed from the symbol library table. Give the user a chance to save
or revert any changes before allowing changes to the symbol library
table.
Fixes lp:1821691
https://bugs.launchpad.net/kicad/+bug/1821691
When loading a part in libedit, also transfer certain screen
settings to the incoming SCH_SCREEN, from the current
SCH_SCREEN.
Currently, the grid settings are transferred, but this could
also do other settings if needed.
Also remove some duplicate commentary and mention why the
grid is set in a SCH_SCREEN even though the BASE_SCREEN ctor
sets the same default.
Fixes: lp:1815108
* https://bugs.launchpad.net/kicad/+bug/1815108