Example ABC files from the ABC spec do not render correctly

[r4dian]

ABC standard is documented here, with some example files included near the end:

http://abcnotation.com/wiki/abc:standard:v2.1#sample_abc_tunes

Here are those examples in a markdown file: ABC test.md

• Meter changes are not displayed in the song "Old Sir Simon the King"
• In-line meter changes are not displayed in the song "William and Nancy" and prevent it from being parsed at all. (I have removed the abc tag so the source is displayed in the attached file)
• When there’s multiple songs in the same file, it only displays the first one unless you place each one individually in ```abc tags

If this bug should instead be opened against some other project that Stackedit uses to render these files, let me know which.