Further questions about method=napp

[bmschmidt]

Apologies for not browsing through all the release history for this and just spamming you with some not-quite-bugs, but I wanted to raise a few questions about method = napp that aren't fully described in the docs.

1. A few places in the documentation (at least in the function gender) it says that "Germany" is a valid option, but it isn't; in those cases, "Denmark" seems usually not to be listed as an option, though it is, and should probably be added. (Although, there are very few names from Denmark; see the last chart).
2. The year range is listed as 1758 to 1910, but there are only 17 total people (each with a distinct name) in the sample from the first 7 years (all in Norway or Sweden). I clipped the US ipums data to start in 1789 because there are only 419 names in that year (and fewer for those born before); something similar might be appropriate here, probably at around 1776 or so for Norway and later for other countries.
3. It is also might worth flagging in the notes that while "United Kingdom" is included, it is significantly smaller than three of the other countries. I was tempted to use it as a general-purpose method for 1758 to 1789 until inspecting the data file to see how few names there were. Iceland is also small, but probably people know that. Some of the more recent NAPP releases have 100% British samples, so maybe they would fix this.

I'll post that gender_vectors method soon from the other issue I filed, which will incorporate most of this in its default settings, so it may not be necessary to address more than the first issue here.