sslhaf library split plus tidyups

Hi Ivan,

Your recent commits to sslhaf reminded me of the earlier work I did but never
got around to submitting as it wasn't tested.

There was not much in terms of features, but the patches are quite disruptive
in terms of changes to the project structure:
- Unix line endings:
  changes almost every line, so good to get in first
- Split core logic into a separate libsslhaf:
  I simply borrowed the autotools collateral from libhtp for this.  I'm quite awful
  at doing this sort of thing, I have little experience with autotools, so it will pay
  to give this an expert look
- Remove dependencies on httpd-devel and apr:
  This is done in most part by replacing direct library calls with calls to pluggable
  callbacks.  The user of libsslhaf can easily plug in c library or as in the case
  of mod_sslhaf, apr library calls.  In addition to being useful for reducing
  dependencies, this feature also brings other benefits such as allowing library
  users to not only receive logging messages from the library and emit them
  consistently with their applications.  Most importantly, allows library users to
  uphold a consistent memory allocation strategy in their applications, for
  example per thread memory pools.

Please give the changes your consideration - Thanks!