fix bundle install for ruby 1.8.7

Bundler gets removed from the `$LOAD_PATH` for some reason in ruby 1.8.7.
This means we shouldn't try to require something from bundler here.

> Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native
> extension.
>
>        /home/hone/.rvm/rubies/ruby-1.8.7-p371/bin/ruby extconf.rb
> /home/hone/.rvm/rubies/ruby-1.8.7-p371/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in
> `gem_original_require': no such file to load -- bundler/psyched_yaml
> (LoadError)
>         from
> /home/hone/.rvm/rubies/ruby-1.8.7-p371/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in
> `require'
>         from
> /home/hone/Projects/heroku_work/heroku-buildpack-ruby/vendor/syck_hack.rb:15
rework to use psyched_yaml by adding Bundler to $LOAD_PATH
don't need syck hack for bundle version
bump v58
update changelog
Generate jekyll site
Fail build if jekyll site generation fails
output error info for debugging
Write a README for *this* buildpack
Minor README edits.
Pipe errors from jeyll compilation
Patch from @aJanuary. Override jekyll server and autorebuilding in _config.yml
Update build output in README
More README updates.