* I dislike the global infection RSpec does. This commit is a first step
to get a rid of it.
* Also remove the need for `require 'spec_helper` in each spec file with
adjusting `.rspec`.
* 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.
* Add Mutant::AST namespace to hold all AST related data / helpers.
* Mutant::AST will be externalized into an ast-meta gem that can be
shared with unparser for deduplication.
* Over the time the mutators itself will not need to deal with semantic
analysis of the AST anymore by themselves.
* Move AST analysis for send nodes to AST::Meta
* Fix#209
