Stop using compatibility aliases for Pry.config
Move to a fall-through config hash.

This is somewhat easier to understand than the current solution,
but does have some downsides: namely it doesn't work for things like
Pry::Hooks.

It is however the only way I've thought of to let setting
Pry.config.color = work in addition to _pry.config.color =.

For now I've added a hack so that hooks work as they did before,
in future we should work out how to fix them so that only the data
for hooks is stored in the config object, not the hooks object itself.
Inject _pry_ into Pry::Editor
Use _pry_ for consistency
Use _pry_.config in prompts
No Pry.config in easter eggs
No Pry.config in Pry::Indent
Remove occurrences in repl
Make it clearer that we're copying from config to config
Start using Pry::Code#highlighted

Before this change the watch command was broken because Pry::Code#to_s
contained ansi codes which it passed into eval.
Use _pry_.pager instead of Pry::Pager

This is not a concern for backward compatibility as it was introduced
since the last release
Use Pry::Output to strip color when necessary

All credit to johnny5- for this idea:
https://github.com/johnny5-/pry/commit/952568b933f915fa78e193962ca4dca723de8fed

Pros: No longer need to check _pry_.config.color everywhere.
      All color is stripped (not just that added by pry)

Cons: Inefficient to add colors and then remove them again.
Pager should also respect _pry_.config.color
add color more confidently
Fix typo
Merge branch 'remove-global-config'