Merge remote-tracking branch 'fizx/solr4' into solr4

Conflicts:
	sunspot/lib/sunspot/version.rb
Use per-environment cores, and a default, with shared instanceDir and separate dataDir
Update Gemfiles to the latest Bundler requirements
Correctly prepare the Solr installation in an app for multicore
Update to Solr 4.2.0
Make sure travis is testing with rubygems < 2.0 for now
Clarify version support in Travis build matrix
Merge pull request #364 from fizx/solr4

Solr4 compatibility
Fix rails 2.3.16 gemfile for ruby 2.0.0

This allows the travis specs to pass on rails 2.3.16 / ruby 2.0.0.
Update build matrix excludes for ruby 2.0.0
Re-exclude exotic rails 2.3.16 / ruby 2.0.0 build from travis ci

We know the build works fine, no need to test such an exotic combination
all the time.
Merge pull request #387 from felixbuenemann/fix-travis-ci-builds

Fix Travis CI builds for Rails 2.3.16
remove, replace, or use archive.org for dead links in articles list on README
Merge pull request #391 from pduey/master

Removed/Replaced dead links in Tutorials/Articles on README
Rails 4: replaced deprecated finder option "include" from find_in_batches options
added compatibility for rails 2
Merge pull request #393 from christophemaximin/fix_find_in_batches

Rails 4: replaced deprecated finder option "include" from find_in_batches options
enabeled sunspot task when running with Rails 4