Check test coverage and increase/fix where necessary

[leejo]

Check existing test coverage with Devel::Cover, et al, and increase where necessary. I would like to make sure we have a good level of test coverage, this can be done as a rolling task when addressing other issues.

[leejo]

4364c01 added coveralls hook in travis CI, which is currently reporting 87%. I believe this figure is wrong due to CGI.pm's autoloading optimisation that string evals most of the module's subroutines - this is a compile time optimisation that needs to die. Profile compilation time with and without this optimisation to get better coverage metrics and thus a better understanding of what needs to happen to increase test coverage.