add tests for custom indentlevel

The desired behaviour is that passing an :over<n> option on the =begin
line will cause an indentlevel of "n" instead of the default of 4.

See [rt.cpan.org #84488].
refactor: change internal method signature

Pass the entire Region object to the _expand_list_paras method
instead of just its children, since the parent object may hold
a custom indentlevel in its direct content.

See [rt.cpan.org #84488].
allow custom indentlevel (=over) value

Specify "=begin :list :over<6>" for POD with "=over 6" instead of
"=over 4" by default.  Resolves [rt.cpan.org #84488].
unmark tests for completed functionality as TODO
changelog for next release
show what the pod would look like in each example
note where each rendering ends
v0.101621

          allow :over<x> for custom =over indent level (thanks, Alex Peters!)

          add fully rendered examples (thanks, Karen Etheridge!)

          update bugtracker and repo