Add documentation and templates for rebar releases

Add the rebar-templates directory and the files it contains to provide
rebar templates for creating Erlang releases that use Yaws. Add
www/rebar_release.yaws to provide documentation for using the templates and
creating releases.
Add yapp appup and c_src *.d files to .gitignore
Minor release tweak
Update build instructions

The build instructions now comply with Christopher's notes
at http://sourceforge.net/p/erlyaws/mailman/message/32571909/
Merge pull request #189 from zxq9/master

Update build instructions
Properly handle Yaws installation if a previous version already exists

From version 1.99, /usr/lib/yaws is a symlink on
/usr/lib/erlang/lib/yaws-{VSN}. In previous versions, this was a directory. So
we must remove this directory to create the symlink at the right place.

Because this directory can contain user data, we rename it instead of removing
it.
Fix regular-install script by using $(logdir) variable
Do not use hostname to generate default yaws configuration

Fix issue #191
Do not test Yaws anymore on R14B02 on Travis platform

It seems that we hit the bug OTP-9214 on Travis. This has worked in the
past. But now, for an unknown reason, the testsuite fails on R14B02 because of
this bug.
Show report.log if yaws is not started during a test
Fix commit adb3c360
Use default notification policy for travis
Require Erlang/OTP R14B02 or higher to compile Yaws
Rework how SSL protocol_version is handled

* Don't ignore SSL protocol_version in embedded mode

* Stop setting global default SSL protocol_version

* Warning that R16B01 is required to SSL protocol_version
    After testing R14B02+ with `application:set_env(ssl, protocol_version, X)`
    and passing `versions` to `ssl:listen`, it looks like only R16B01+ follows
    the settings.

    References:
      - https://travis-ci.org/capflam/otp-ssl-test/builds/44369449
      - http://erlang.org/pipermail/erlang-questions/2014-October/081388.html
      - https://github.com/klacke/yaws/pull/192

Fix pull request #193
Add Andrei Neculau in the contributors (and sort them by name)
Add Erlang/OTP 17.3 support in .travis.yml
Renew self-signed ssl certificat