Refactor parts of the code and add more tests

This is a refactor of parts of the code, some minor things such as adding
punctuation in the end of sentences and making the code a bit easier to read.

More tests has been added in the form of gometalinter which checks the code
health, style and spelling errors. The flaky cleanup test should also be fixed
with this commit.

.travis.yml

@@ -1,10 +1,14 @@
 language: go
 
 go:
-  - 1.2
+  - 1.5
+  - 1.6
   - tip
 
-script: make test
+script:
+  - make get-deps
+  - make metalint
+  - make check
 
 env:
   - PGSTORE_TEST_CONN="postgres://postgres@127.0.0.1/test?sslmode=disable"
@@ -13,6 +17,6 @@ before_script:
   - psql -c 'create database test;' -U postgres
 
 addons:
-  postgresql: "9.3"
+  postgresql: "9.4"
 
 sudo: false