Unpack sqlite dep dynamically

This change allows us to only store the compressed (`tar.gz`) sqlite dependency in git. I really did not like having to store the uncompressed sqlite dependency because it makes upgrading a pain and the diffs enormous (which was a problem previously because other commits were added when sqlite was updated making it hard to see what changed).

This also adds a variable called `sqlite`. This enables you do do:

```sh
node-gyp configure build -v --sqlite=/some/custom/path
```

In order to build against an external sqlite version. So, to build against sqlite3 in `/usr/local/lib` you would do:

```sh
node-gyp configure build -v --sqlite=/usr/local
```