Font doesn't support characters beyond basic ASCII

[Formedras]

The spritefont YARG uses by default seems to only support the basic ASCII codepage, causing characters beyond its bounds (including characters in Windows-1252 and CJK languages) to not be rendered.
This seems to have been addressed before (in issue #760) but still persists as of b2870. For example, most German songs, such as Hier Kommt Alex by Die Toten Hosen, will have characters with umlauts (such as ü) and the eszett (ß) be missing.

Here, the two lines Damit man täglich roboten geht / Ist die größte Aufregung, die es noch gibt are both partly visible, and multiple characters are missing.

At the very least, due to international songs, characters used in Latin-script European languages should be included in the default font.
If YARG can't support CJK (or other languages) due to size limitations (as the prior issue states), there should also be some way to use system-installed fonts that do support the desired text.

[HaleyHalcyon]

Encountered the same issue playing an English language song (California Über Alles)

[Formedras]

German characters (umlauts, eszett) are working as of b2876. Wouldn't know about any other languages or which songs to use to check them with. (Such as French accents and cedilla, Nordic overring and ø, Japanese Katakana and Hiragana syllabaries, Korean Hangul alphabet, etc.)

Japanese is likely low priority due to its being well mapped to Latin script, and the fact that officially-released Rock Band songs in Japanese are pre-romanized (such as from Dir En Grey). Korean should be higher, as romanization is less-well mapped (differentiating between similar syllables often requires extensive diacritics or numbering). Chinese is in a similar boat as Korean, except that characters are mapped to whole words rather than syllables or letters, entirely preventing the use of pre-baked spritefonts. (Not to mention the differences between Simplified and Traditional Chinese, which is its own huge barrel of worms.)