Fixups for body-decoding.

  Not 100% sure this is correct, but it is progress.

  This is part of #101.
  Removed attachment addition to mails.

  This breaks functionality temporarily.   I'd like to further
 consollidate the compose()/reply()/send_mail() primitives, but
 for the moment I've taken the least controversion minimum
 action.

  This is almost the final part of #101.
  Fixed bogus embedded TABS + braces.

  This allows `make style` to complete with zero errors.
  Added comment to describe the purpose of add_attachmens_to_mail().

  This is the final part of the transition to GMime.

  Updates #101.
  Removed mimetic usage. Make GMIME mandatory.

  I've removed the conditional-compilation, and made GMIME
 usage the default.  The code is complete for all the common
 cases - the only omission is the addition of attachments
 to outgoing mails.
  Changed build-deps from libmimetic to gmime
  When we fail to find a text/plain part we fall-back to
 reading the body of the message manually.

  This is suboptimal but seems to work on my mail archive.
  Use the correct hostname in CMaildir::message_in.

  We previously used mimetic for this, then reverted to "localhost"
 as part of the GMime transition - #101.
  Change build-dep to refer to GMime.

  This is part of #101.
  Linking fixups.

  -lpcrecpp is sufficient, -lpcre is redundent.
  Remove mimetic-namespace.

  Also the std::namespace, which required qualifying the use
 of ofstream + ios::binary with a std:: prefix.
  Removed old mimetic debugging code.

  Now we're not using mimetic we don'tn eed this code.
  Removed the mimetic-debug-code.

  Now we're not using mimetic we don't need to keep this,
 as it no longer corresponds to the code we're running.
  Removed last trace of mimetic.

  We were needlessly pulling in the mimetic.h header-file.

  This is a random part of #101.
  Added missing include file, to fix compilation error.

  I assume the removal of `mimetic.h` contributed to this.
  Add attachments to outgoing messages.

  This updates #101.  We add attachments correctly, but the
 message needs an explicit text/plain MIME-type to resolve
 this.
Use correct type for 'found' to avoid bad comparisons
  Fixed style-issue.  We don't like "// comments".
  Avoid using a fixed filename.

  We didn't need to use a fixed/predictable filename for our
 mime-encoded outgoing-message I just did that for debugging purposes.

  Now we overwrite the file.
  Ensure that msg_filter is invoked.