Provide more context in the error messages

Now the error messages are prefixed with the method (GET, DETELE, PUT,
or POST) and the resource that was being operated on.
Suppress script line number from error messages

The _error function was returning a message with trailing newlines
stripped off so that when the message was croaked Perl appended a script
name and line number to it.

Now _error returns messages with a single trailing newline to make Perl
be less verbose.
Add REPOSITORY section to documentation
v0.011

  [Changes]

  - Provide more context to and suppress script line numbers from error
  messages in the error messages.

  - Released at #cpanday.