The 3.x Suggester was in fact Spellcheck. the 4.x Suggester is a real Suggester now.

* run solr on travis

* use java 9

* fixed matrix

* added a first intergration test that select a result from the Solr techproducts example server

* added comment and dummy assertion to testPing()

Cleaned up suggester query and added missing parameters

Fixes bugs from PR 484; fix Http adapter for extraction requests

Make suggester query use suggest prefix

Fix: Remove unused imports

Fix: Cache dependencies installed with composer between builds

Fix: Remove useless override

Fix: Use more appropriate assertion

Fix: Remove useless return statements