Support of Multi-line Metadata Fields such as in Letterhead Support File

[cdhutch]

I've upgraded to MMDv6 and am updating all of my MMDv5 templates. I've read through Issue #58 and understand that you've changed the method that you parse whitespace.

I'd like to be able to use your Letterhead Support File, especially the ability to enter a multi-line address in the metadata for subsequent parsing and LaTeX compiling. I've attempted to create a workaround using your new raw syntax to insert multiline latex into the file, but I can't figure out how to squeeze the latex code in before the \input{mmd6-letterhead-begin} line without disrupting the metadata parsing.

Would you consider enabling a few additional metadata fields to process raw LaTeX strings, as you have done with latexauthor and latextitle or providing a more general approach to parsing multiline metadata? If there is a workaround technique to provide this functionality, I would appreciate you sharing that.

Thank you for the great software. It has been a significant part of my workflow for the past few years.

[fletcher]

I'll try to think of a more general solution than "whitelisting" a few fields.

[cdhutch]

Thank you, Fletcher.

[fletcher]

Now you can do something like this:

Title:	Test Letter  
Date:	September  1, 2018  
Recipient:	Mr Smith  
Recipient address:	123 Main St\
	Some Town, ST 12345  
Graphic signature:	true  
Base header level:	2  
Latex mode:	memoir  
Latex config:	letterhead  
Use XeLaTex:	true  


[%recipientaddress]

Dear [%Recipient],

It doesn't affect any of the existing tests, but there could potentially be a side effect under rare circumstances. I'll keep an eye out for trouble and change/reverse as needed.