Add travis job to run test suite with solc nightly (#902)

Job is allowed to fail, and is run just for information purposes

scripts/test.sh

@@ -54,6 +54,11 @@ else
   start_ganache
 fi
 
+if [ "$SOLC_NIGHTLY" = true ]; then
+  echo "Downloading solc nightly"
+  wget -q https://raw.githubusercontent.com/ethereum/solc-bin/gh-pages/bin/soljson-nightly.js -O /tmp/soljson.js && find . -name soljson.js -exec cp /tmp/soljson.js {} \;
+fi
+
 if [ "$SOLIDITY_COVERAGE" = true ]; then
   node_modules/.bin/solidity-coverage