Added trueOrFalse(int probabilityOfTrue) to BaseProducer. This allows to
generate non-uniform boolean values. 

The new method may be usefull to generate data, at a specific ratio.

for (int i = 0; i < 1000; i++) {
	// generate company with one person
	if (fairy.baseProducer().trueOrFalse(10)) {
		// sometimes add one more person to the company
	}
}

Also added Eclipse to build.gradle and Eclipse specific stuff to
.gitignore