Fixed ERRAI-671 - Build/Compilation hangs when running with only one CPU

We need at least two threads to run a code generator. One for the generator itself and one for the reflection scanner which is used by all generators. The problem was that we initialized our ExecutorService with a fixed sized thread pool sized by the number of available processors. We now use at least 2 threads or the number of processors if it's higher than 2.
The pom defined an argLine for forked java processes that contined an line break which prevented the tests from running successfully. Removing the line break fixes this issue.
During the build of the project some files are generated in a sub folder of the src directory. Because the project does not contain a git-ignore file these files show up as untracked files in git which could lead developers accidentally adding these files. Adding an ignore file solves this issue
Merge pull request #72 from gkropiunik/master

errai-cdi-async-databinding-tests not working on Windows and untracked files in errai-aerogear-demo
Fix validation test-case failure message.
Rename @AltLogger to @NamedLogger
Client CDI classes were not devoted when the package name starts with `client.`

Follow up of ERRAI-465
Fix and regression test for ERRAI-672
Added unit test for ERRAI-672
Added `-out` parameter to Errai's JUnitShell

`-out` is a deprecated but valid argument for GWT's JUnitShell. Applications which
use `-out` failed with `Unknown argument: -out` when `errai-weld-integration` is
on the classpath.

For reference: GWT 2.5.1 JUnitShell
https://github.com/gwtproject/gwt/blob/2.5.1/user/src/com/google/gwt/junit/JUnitShell.java#L167