Reify shared example groups as a first-class type.

- Allows us to provide pretty `inspect` output, which
  is far better than the anonymous module output we
  normally get.
- Simplifies the creation of the shared example group.
  Previously each group instantiated a module and defined
  `included` as a singleton method.
Merge pull request #1753 from rspec/reify-shared-example-group

Reify shared example groups as a first-class type.
Initial appveyor.yml file.
Appveyor build updates.

- For now build only one ruby version.
- Windows does not support symlinking.
- Ansicon is needed for color.
Update matrix.
`[.]` doesn’t appear to work well on windows.
See what the host os is repotted as on appveyor.
Fix windows pending logic
Force non-ANSICON environment.

On appveyor we install ANSICON.
[TMP, WINDOWS] excludes lines from rspec libs by default
[TMP] Reducing noise for a sec
[TMP, WINDOWS, +1] excludes lines from rspec libs by default
[TMP] Trying out my fork of `rspec-support`
Add escape
[TMP] Read-only git earl
[TMP] rubocop
[WINDOWS] BacktraceFormatter, excludes rspec files
[WINDOWS] Getting closer
[WINDOWS, => GREEN] BacktraceFormatter works as expected
[CI] Just run spec/ not all