add simple URL runnable example

[schimmy]

Optimus is sufficiently complex that we should have a few runnable examples to show off the power and provide a guide to new users.

I've added a examples directory and this is the first simple example. I'd also like to add (in separate PRs):

• group by
• join
• writing to s3 without using disk
• sort, map, & reduce (MapReduce on the cheap! although still in memory :/)

[schimmy]

I would like to push this, and figure out the godoc later. I don't have time right now to figure out this stuff (even though I'm sure it's not too hard), and I do want the gophercon people to have an example they can run when they are reviewing the proposal!

The test failure is due to it being on a branch and the example package not existing yet, this all passes locally.

[azylman]

@schimmy It looks like your example doesn't run anymore because it doesn't have a main function. Also, it breaks the tests. After those are fixed you can merge.

[schimmy]

reverted to the earlier version - I'll push this and then make runnable in the future