Unpack sqlite dep dynamically and move build node_sqlite3.node module into ./lib folder

add support for dynamically unpacking the bundled sqlite3 dep to avoid having to store the uncompressed files in git

Conflicts:
	test/fts-content.test.js
	test/scheduling.test.js

fix scheduling.test.js against variable sqlite3 versions - closes #122 (thanks @tomhughes for initial patch)

fix the fts test added in 42aa8c88, which was not valid for expresso and must never have worked (just hung)

Updated for libuv changes in node 0.10

Updated to sqlite 3.7.13

Add note about installing node-gyp.

Use the new uv_ref()/uv_unref() API for node >= v0.7.9, and remove a couple
unnecessary instances of uv_ref()/uv_unref() where only uv_queue_work() was
being used.