Remove orphan IsString instance for URI (we shouldn't be doing this.)
Fix test failure due to IPv6 localhost
Merge remote-tracking branch 'andrew/master'

Conflicts:
	tests/TestServer.hs
A couple of tweaks:

  * encode/decode URIs correctly; URIs are Unicode and
    Data.ByteString.Char8.[un]pack will mangle them.

  * turn certificate verification off on Mac and Windows rather than just
    bombing out if we try to use SSL there

  * shorten `mappend` to <>

  * stop calling "withOpenSSL" every time we download a URI; not only is it
    expensive, but I don't think it's safe to call SSL_library_init() multiple
    times in a multi-threaded context. Instead put a warning message in the
    docs asking the user to run it in main.
Merge branch 'gcollins'
Revert non-Linux certificate verification

Restore existing behaviour that the default is certificate validation
against /etc/ssl/certs. Open task to non-free operating systems to
find an appropriate default configuration if that is possible

Consolidate documentation of withOpenSSL requirement.
Rename generalPurposeHandler to concatHandler'