Reorganize and standardize TestML testing

All .t files now use Test::More and call done_testing.  done_testing
has been removed from run_all_testml_files.

Some TestBridge functions have been renamed and all have been documented
with some comments explaining their use.

All perl test points are now array references for consistency and to
allow testing dumping multiple Perl references.

    --- perl
    [ $ref1, $ref2 ]

t/tml-local files have been split into subdirectories by the test
bridge function they use.  .tml files with multiple test types
have been split out.  All files in a directory now are expected
to use the same testing function.
reimplment t/tml in perl

This is an approximation of the original bash t/tml program.  It
uses regular expressions instead of globs, but the end result
seems pretty similar.

Documention is in POD.
start splitting local tests up by spec topics
split nullref tests by data type
split 03_regression by data type
make tml file names singular
merge nesting.tml into collection.tml
split 02_basic by data_type
write_string called as class method returns empty string
rename tml-world files with legacy names
Small doc changes