[WIP] make more Symfony2 console friendly, make runner more flexible

I put these together not because they logically fit together but since I am using this more as a play ground for things I am testing out.

it includes https://github.com/zendframework/ZendDiagnostics/pull/9 and https://github.com/zendframework/ZendDiagnostics/pull/10

relevant commits:

1) Symfony console friendliness
https://github.com/zendframework/ZendDiagnostics/commit/356fce5b2cae4a374a8f58026f1954e06a376efe
see also https://github.com/liip/LiipMonitorBundle/pull/33/files#L7R24

2) making it possible to run individual checks
https://github.com/zendframework/ZendDiagnostics/commit/c11ab6ab3a113973736540775953e157d69e4644
see also https://github.com/liip/LiipMonitorBundle/pull/33/files#L4R41