Cache templates

Output: `ab -n 3000 -c 5 -k http://127.0.0.1:8080/2013-9-9-a-blog-post`

Before:

    Requests per second:    2012.57 [#/sec] (mean)
    Time per request:       2.484 [ms] (mean)
    Time per request:       0.497 [ms] (mean, across all concurrent requests)
    Transfer rate:          2273.97 [Kbytes/sec] received

After:

    Requests per second:    2208.88 [#/sec] (mean)
    Time per request:       2.264 [ms] (mean)
    Time per request:       0.453 [ms] (mean, across all concurrent requests)
    Transfer rate:          2495.77 [Kbytes/sec] received