Done using CMake options whenever possible as part of the build process (closes #354).
Minor update to the developer documentation [ci skip].
Some minor cleaning up [ci skip].
Some minor cleaning up [ci skip].
Done with allowing the contents of the viewer to be copied to the clipboard (closes #355).
Some minor cleaning up.
Added a tooltip to some actions.
Only allow the contents of the viewer to be copied to the clipboard when there is actually some contents.
Done with fixing an issue with the viewer in the raw CellML editing view (closes #356).
Done with fixing an issue with the viewer in the raw CellML editing view (closes #357).
Done with making the looking up of an equation more accurate in the Raw
CellML editing view (closes #359).
Done with only copying the exact contents of the viewer (closes #358).
Reverted our work towards handling a CellML API crash when when trying to generate code for a malformed CellML file (#340).

Indeed, there was (clearly) a fundamental issue with the CellML API, so
it really ought to be fixed there than have us handle a possible crash
of the API.
Reverted our work towards handling a CellML API crash when when trying to generate code for a malformed CellML file (#340) [ci skip].
Done with handling a CellML API crash when when trying to generate code for a malformed CellML file (closes #340).

Done with handling a CellML API crash when when trying to generate code
for a malformed CellML file (closes #340).
Done with handling a CellML API crash when when trying to generate code for a malformed CellML file (closes #340).
Some work on adding a list to the Core CellML editing plugin (#360).
Some minor cleaning up.
Some minor cleaning up [ci skip].
Some minor cleaning up [ci skip].