core: FIX: hot reloading was not working properly anymore

Contrary to what I think using a new classloader is not enough to get classes reloaded.
Therefore I use a HotReloadingClassloader to reload classes and a URLClassloader pointing to destination dir to reload resources.
spec: add seconds to title when recording specs

This makes it possible to records several specs per minute, very useful during presentation (and also maybe day to day use).