Simplify __virtual__function
Remove needless regex checks

Using socket.inet_pton() is more efficient, and less error prone, than
using regexes.
Alias lowercase versions of functions
Log dig command output at debug
Make dig.SPF recurse include and redirect entries
Fixed unit tests

Had to skip two tests because I don't know how to mock properly when
recursion is involved.

Also made some PEP8 fixes.
Fix dig tests

Added a side_effect function to allow for testing of recursive functions
in the SPF tests. Also enabled all skipped tests as they now all pass.
Fix bug in dig.SPF when processing redirects

This fixes a bug where dig.SPF would infinitely recurse on redirects
because, instead of looking up the redirect domain, it was looking up
the domain initially passed to the function.
fix pylint (add blank line)
Merge pull request #10403 from terminalmage/10367

dig.SPF fixes