also test building against external libsqlite

.travis.yml

@@ -10,8 +10,14 @@ install:
  - npm install mocha
  - npm test
 
-before_script: "make clean"
+before_script:
+ - make clean
 
 script:
  - npm install --stage
  - npm test
+ - sudo apt-get -qq install libsqlite3-dev
+ - make clean
+ - npm install --build-from-source --sqlite=/usr
+ - ldd lib/binding/*/*/*node
+ - npm test