Many bug fixes. With this fixes I was able to test my own Tasks! :)

Hi,

I used your component for the deployment of some project. Rollback, versions, rsync, targz are nice features! :+1: 

Though I found a bunch of problems when I tried to write tests for my own tasks. In the end I was able to do that but that required some changes to the component. I tried to keep backward-compatibility and not to break anything but there are no tests :(. I will try to write some tests for the component if this new deployment takes off. 

Short summary of changes:
 - improved autoloader to support loading custom classes when the component is compiled as phar; refactorings related to autoloader
 - fixed a bug ("releases list to:environment" failing); refactored a bit DeployCommand
 - refactored Config (required to be able to mock Config)
 - feature: contents of "hosts" file can also be formatted as json array
 - other minor fixes: BaseStrategyTaskAbstract to respect "symlink" setting