A regexp to extract 'Subject Alternative Name' doesn't work when the domain use a minus character.

For grep regexp, to lose its special meaning inside brackets, the minus character must be placed in the first or last position in the list.

https://www.gnu.org/software/grep/manual/grep.html#Character-Classes-and-Bracket-Expressions

- use \n as delimiter for read to array
- use \n as delimiter for comparing SANs

Fixes #612

Fix bug with nslookup server param

Fixes #347 and #400

The dns query is often being reprinted as a comment as part of the drill/dig output
this caused multiple hits for the grep, making the comparison invalid.
Make sure we strip out comments before we look for the challenge text in the txt record.

getssl updets itself by:
- checking for a new version
- if so:
  - download the new one into a tmp location
  - rename the current one to name with version appended
  - rename the tmp file to the current location
  - run the new version
If the renaming fails, the old version gets run, which again downloads, etc.
Now exit if the rename (install command) fails.