Automatically wrap multiline deprecation messages

Fixes #1336
Use String#lines to detect multiple lines
add legacy support for colorize_summary
Add missing changelog entry for the addition of hook scope aliases

Related to #1174.
Merge pull request #1426 from yujinakayama/missing-changelog-entry

Add missing changelog entry for the addition of hook scope aliases
Extract thread local metadata into a single variable.
Remove misleading comment.
Prevent creating an isolated context when already inside a context.
There is no reason to do this, and it could potentially cause unexpected
bugs.
Merge pull request #1429 from rspec/issue-1349

Prevent defining nested isolated contexts
Remove file existence conditional.

Since we collapsed all the HTML fixtures to be the same file, we no
longer switch on platform.
Merge pull request #1431 from rspec/issue-1366

Remove file existence conditional.
Combine drb_command_line and drb_options into one file.

These classes are related and will either be used
together or not at all. Seems better to just have
one drb file.
Merge pull request #1428 from rspec/legacy_support_for_colorize

Add legacy support for colorize_summary
Add doc comment to get back to 100%.

Not sure why this is suddenly needed...
Merge pull request #1350 from rspec/deprecation-formatter-fenceposts

Automatically wrap multiline deprecation messages
document default colors
[skip ci]
Merge pull request #1440 from rspec/document_default_colors

Document default colors
Merge pull request #1438 from rspec/drb-reorg

Combine drb_command_line and drb_options into one file.
Improve docs some more.
Move methods only needed by our tests into spec_helper.