Update testing instructions in the README after the Solr mirror went away

This uses the canonical Apache archive which should be more stable than the mirror we were using
Bump requests dependency to 2.x for Unicode handling
Move test setup to script & update README

This avoids the README drifting out of sync
Use tox for testing multiple versions

* Add a simple test-runner which handles starting and stopping Solr
* Added a basic tox.ini for Python 2.6, 2.7 and 3.3 with and without
  Tomcat to keep us honest about extra_requires…
Enable Travis CI
Skip tomcat error tests when lxml is unavailable

Until _scrap_response has a Tomcat path which doesn't depend on
lxml.html there's no point in running these tests on a different config
Tests: expect content extraction to fail

Once https://github.com/toastdriven/pysolr/issues/90 is fixed we can
re-enable this test
Tests: update test_full_url for multi-core config
Tests: set Tox basepython versions for tomcat tests
fixed both issues https://github.com/toastdriven/pysolr/issues/96 and https://github.com/toastdriven/pysolr/issues/90 and updated test solr sever from 4.1.0 to 4.6.0. All tests pass
remove unnecessary comment
Merge pull request #104 from tongwang/master

Fix content extraction (thanks @tongwang)
Bumped to v3.2.0!
Merge tag 'v3.2.0'