implement fix for issue #139

This adds a mutator that replaces non-void method calls with one of its
parameters of the same type as the return value in case such a parameter
exists.

Thanks to @smandel for showing me how to use ASM and working on a first
draft of this with me.
test for case when return value is not used
refactoring
test that mutator is listed
update copyright information
rename mutator to "argument propagation"
Merge branch 'UrsMetz-replace-method-with-parameter-of-matching-type'
mark argument propagation mutator as experimental
update readme
[maven-release-plugin] prepare release pitest-parent-1.1.1
[maven-release-plugin] prepare for next development iteration
fix version
test should live in test tree
fixes 150 - last line sometimes missed from coverage
[maven-release-plugin] prepare release pitest-parent-1.1.2
[maven-release-plugin] prepare for next development iteration
update for 1.1.2 release
a little javadoc
fix broken java8 build
cleanup