Re-enable solidity coverage

- Upgrade version
- Re-enable in travis.yml
- Move mocks to contracts folder for instrumentation

.solcover.js

@@ -1,5 +1,9 @@
 module.exports = {
     norpc: true,
     testCommand: 'node --max-old-space-size=4096 ../node_modules/.bin/truffle test --network coverage',
-    skipFiles: ['lifecycle/Migrations.sol']
+    compileCommand: 'node --max-old-space-size=4096 ../node_modules/.bin/truffle compile --network coverage',
+    skipFiles: [
+        'lifecycle/Migrations.sol',
+        'mocks'
+    ]
 }