Add option to `TREMLWriter` to render either "flat" or formatted code

[delphidabbler]

At present TREMLWriter renders it's output formatted with indents, which is what is wanted normally. However for storing in output files (and when pasting code into the database) a flat format with no indents or line feeds is more useful.

Therefore an option to render either way would be useful.

[delphidabbler]

This has been implemented in the vault branch at commit a7959cf

[delphidabbler]

This has been implemented in the vault branch at commit a7959cf

Since this request has been implemented in vault, there's little point in duplicating that effort here.

If vault fails we can revisit the issue, but until then this issue is being closed.