* Do backslash escape parsing in parse_kv() [was being done in the copy
  module purely for newlines in the copy module's content param before]
* Make parse_kv always return unicode
* Add bandaid to transform args to unicode until we can fix things
  calling parse_kv to always send it unicode.
* Make split_args deal with unicode internally.  Warning, no bandaid for
  things calling split_args without giving it unicode (shouldn't matter
  as dealt with str internally before)
* Fix copy and unarchive action plugins to not use setdefaultencoding
* Remove escaping from copy (it was broken and made content into latin-1
  sometimes). escaping is now in parse_kv.
* Expect that content is now a unicode string so transform to bytes just
  before writing to the file.
* Add initial unittests for split_args and parse_kv.  4 failing
  tests.because split_args is injecting extra newlines.