Find out what breaks parallel execution

[jpommerening]

When webpack builds mulitple PDFs in parallel, node-java throws a weird exception.
We should either find out what causes this, or make sure JVM related things are called sequentially.

[jpommerening]

Hmm … it seems the two garbage collectors are fighting over the LogWriter proxy. (Well, once you get past the .some( ... instanceOf( ... ) ) thing by just recording somewhere that the logger is initialized.)

I implemented the colorizing log writer in Java, successfully eliminating the problem.

/cc @alex3683

Btw. One-and-a-half-liner to compile the Java files:

docker run -i -t -v $(pwd):/tmp/pdfr -w /tmp/pdfr java:7-alpine \
   javac -cp java $(find java -name "*.java")

[jpommerening]

Fixed on master (v0.3.0)