Response improvements, some tests, and deployment script

It’s been a long time since I made a pull request. This one is huge, and I’m sorry for that. It’s basically all that I’ve been working on, regarding some important topics for Bottle.

I first enhanced the Response object. We can now send custom headers, and use some utility functions, such as redirect(). More utilities functions, such as an `@ajax` decorat^wannotation, will come soon.

I also started to write tests. Only some functionnal tests are written now, because I spent most of the time building the test environment: a web server is spawned in background with the tests in order to run the Bottle application in a real-world way. It’s related with issue #2 .

Finally, I wrote a script to make a PHAR archive from the entire Bottle framework. I think it’s more efficient than trying to pack PHP code in a single file, and also much easier to deploy. I moved the Bottle sources to the `src` dir to make the archive work easier. I also made a new branch, `deployment`, which will contain only the phar file, for easy deployments with git.

My next move will be focused on documentation, testing and stability.
Would be better to use some wrapper fn for such lines to avoid hardcoded domain and produce alternate way to grab page contents