fix #4 Support Report Naming to be multiproject compatible

[mbauhardt]

Why
I want to use the jmh report plugin on a multi project build.
At the moment, this plugin can handle only one report in a single project. In a multi project env the results will be overwritten by each other.

How
Introduce reportName attribute to be able to render a unique name for each report.

Furthermore,
with that change set, the project view doesn't make any sense now. Because the actual report (in case of a multi project) sticks in the module itself and not in the project anymore.
For that reason the whole project view stuff is deleted within this change set.

[AlexChrbn]

Could you update the readme please?

[jzillmann]

I feel the the project level functionality (compare all runs against each other), is essential since it allows to keep track on how the project is developing performance wise.
Thus I don't want to remove it. I understand the need of a multi-project support, but I think the way to go is to merge the module reports to a single report.

[AlexChrbn]

For me, it would be great to have categories. It'd be like implemented in this PR, but i would just create multiple files, each a different category with different links in the Jenkins view.

[jzillmann]

@AlexKroeker So for a Jenkins run you would basically have one report per submodule ? And for the project view as well ?

[AlexChrbn]

@jzillmann That would pretty much be it.
Basically, it's enough for me if multiple reports can be added (e.g. via a regex) and each report is accessible via a standalone link in Jenkins.
Plus, an overall view would also be beneficial.

[jzillmann]

Ok, sounds fine. Do it! :)