update dependencies, with report from lein-ancient

Tests still passing, this is the output from lein-ancient now,
jsonevent-layout and netty must remain at these versions for now.

```
[net.logstash.log4j/jsonevent-layout "1.6"] is available but we use "1.5"
[io.netty/netty "4.0.0.Alpha8"] is available but we use "3.8.0.Final"
[log4j/apache-log4j-extras "1.2.17"] is available but we use "1.0"
[org.antlr/antlr "3.5.2"] is available but we use "3.2"
```
Merge pull request #359 from pyr/new-dependencies

update dependencies, with report from lein-ancient
folds/maximum and folds/minimum return nil when no metrics present
Merge branch 'master' of github.com:aphyr/riemann
Fix query-for-host-and-service-test crash

when evaluating and expressions like (and (= metric 2)) things were fine, but
not when evaluating something like (and metric), no bueno!
streams/smapcat
Clean up deprecation of combine; silence tests, etc.
little tidying for hipchat
Merge pull request #364 from stuarth/hipchat-cleanup

little tidying for hipchat
Ugh, reorder combine after smap*.
Merge branch 'master' of github.com:aphyr/riemann