* Before Mutant::Expression was not marshallable resulting in the need
to build "partial" result objects from killforks.
* Fixes an adjacent bug in spec selection
* Flattens the rspec example groups on filtering to remove redundant
work being done on executing subtrees of already executed example
groups
* Uses test batching to kill one mutation per isolation that results in
a significant speedup.
* Drop rspec 2 support.
[closes#256]
* Nuke around 800 lock
* Honor LSP with not anymore squeezing something non LSP compatible in
the same inheritance tree.
* Separate running from result tree.
* Clean up kill logic and early exits on already dead mutations.
* Fix #runnin? smell for reporters.
* Decouple config object from VM state. Makes it serializable to enable
config loading.
* Fix sequence of global VM events to match PRIOR rspec infects VM with
gazillions of classes / modules. Thix fixes a startup speed
degeneration.
* Various fixes to enhance determinism.
* Replace some unneded manual double dispatch with single manual dispatch for
reporter / runners.
