Remove SQLite3 dependence

[hlechner]

It can be replaced by some javascript solution, as examples:

kripken / sql.js:

• https://github.com/kripken/sql.js

NeDB:

• https://github.com/louischatriot/nedb
• http://blog.mongodb.org/post/55693224724/nedb-a-lightweight-javascript-database-using
• http://reidburke.com/2013/08/01/nedb-sqlite-for-node/