Major revision in progress
Re-implemented Regexp message matching for meta-matchers

- current spec status: 141 examples, 40 failures
Progress on :respond_to built-in matcher rebuild
Completed update of #respond_to matcher and updated documentation
Refactored #construct matcher
Updated documentation for #construct matcher
Refactored #have_accessor to #have_reader for disambiguity
Refactored #have_mutator to #have_writer
Added :custom_double mocks extension
Finished #have_property matcher and added to documentation
Created BaseMatcher, rebuilt ActiveModel::HaveErrorsMatcher
Updated specs for BaseMatcher, ActiveModel::HaveErrorsMatcher
Added core be_boolean matcher

- current spec status: 195 examples, 8 failures, 1 pending
Updated BuiltIn::BeAKindOfMatcher
Updated documentation for BuiltIn::BeAKindOfMatcher
Rebuilt Core::ConstructMatcher
Updated BuiltIn::RespondToMatcher

- current spec status: 231 examples, 3 failures, 1 pending
Updated BuiltIn::IncludeMatcher
Updated Core::HavePropertyMatcher

- current spec status: 266 examples, 4 failures, 1 pending
Updated Core::HaveReaderMatcher