Arcyd: factor out RepoReporterMock

It turns out that RepoReporterMock isn't required if we introduce an
abstraction on the output of RepoReporter.

Update RepoReporter to accept abstract 'outputs' that receive
dictionaries.  Update tests to use a simple SharedDictOutput.  Update
abdi_processargs to use SharedFileDictOutput.

Test Plan: $ ./precommit.sh
Arycd: dev-status-html: rewrite, add helper script

Add helper script 'status_html_testbed.sh' which uses
'arcyd dev-status-html' to generate pages and then display them with
chrome.  This provides a simple dev environment for quick iteration.

Update abdcmd_devstatushtml to use abdt_reporeporter directly.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/status_html_testbed.sh
Arcyd: add 'repo name' to status reports

Repo status reports now have the 'repo name' as a heading at the top.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/status_html_testbed.sh