remove the documents method

Because YAML.pm will eventually become object oriented, YAML::Tiny will
need to figure out if/how to adapt to that API.  Therefore, we shouldn't
add to the YAML::Tiny OO API because it will make future reconciliation
that much harder.
make all errows throw exceptions
revise and reorganize Changes for exceptions and testing work
clarify that the exception change provides consistency
Move the deprecated variable next its code
Delete irrelevant commented out code
Refactor regexes:

Moved re-s from a container hash to simpler package lexicals.

Code reads clearer. Am I forgetting something peculiar?
Don't return after _error

the method now croaks.
First pass review notes.
move flock code down to bottom

It's weird to have this guts checker up top.
Move the code into more regular layout

Put all the api functions/methods at the top. Easier to see/understand
the API at a glance.

Rename the private methods to more correct/grokable names.

There is more to do, but this is a good commit place.
Rename internal functions

_write_* → _dump_*
_read_* → _load_*

The code is now laid out very regular:

* package preface
* api
  * export functions
  * OO methods
* private/internal methods
  * load internals
    * hash/array/scalar
  * dump internals
    * hash/array/scalar
* helper internals
* documentation

That's it!
simplify code and possibly use less resources.
more language tweaks
Doc comments and tweaks

Remove the exception for the Dump/Load API drop-in replacement to YAML.
It's no different than YAML.pm.
Make a few changes to stay under 80 char wide.

It seemed like there was effort to have code width be limited, so I just
did a tiny bit of reformatting.
oops. left in a 'use XXX'
xdg comments
remove mention of write_utf8_string from Changes, as it has been removed
prevent warnings when Scalar::Util is missing or broken

YAML::Tiny used to not use warnings, and the Scalar::Util
detection/fallback code wasn't properly updated when warnings were
added.  This revises the version check and the fallback code to work
without warning.