Test Coverage

[pryrt]

Coverage has fallen way out-of-date; there are significant error-handling sections that should probably be added -- even if I don't get to 100%, I should go through the coverage holes and see if there are easy fixes before releasing v0.006.

[pryrt]

I've made drastic improvements in v0.006, but there are a lot of conditions and branches that aren't tested; I'm finding most are x//''-type in debugging statements (which are useful when I'm debugging changes, not for the end-user) and other defensive-coding choices.

Most importantly, all subroutines are tested (except maybe a mysterious sub in Editor.pm which it won't identify in the sub-coverage page, despite saying 98.1%)

I'll leave this one open (renamed without v0.006 in the name), but getting to 100% coverage won't be doable in a reasonable amount of time, and I want to release a version that handles NPP v7.9.1 and newer