Custom hydat download path fix

[Travis-Simmons]

Previously if you supplied a 'dl_hydat_here' argument to the 'download_hydat' function it would make it all they way to the end of the function correctly, but then it calls hy_check with no argument. Which does not consider your custom path and causes an error. By supplying the path as an argument it fixes the 'download_hydat' function.

[boshek]

Thanks for this. The test failures here are unrelated to your PR but I think a test would be good here to have caught the change made in #181. Really this download function needs to be split into multiple small functions (though that's not your problem!).

[boshek]

@Travis-Simmons is writing a test for this something you'd be able to do to complete this PR?

[Travis-Simmons]

@boshek I am willing to write a test for it, but I am unsure how to do that! If you comment some documentation on how to write it, I will give it a go next weekend.

[boshek]

Actually I don't even really think it needs a test. But can you please write a NEWS entry and include your GitHub handle?

Something like this:

tidyhydat/NEWS.md

Line 30 in af345e4

- `download_hydat()` now has an `ask` parameter that can be used to bypass the keypress confirmation when downloading the HYDAT database (@rchlumsk, #165).