Coverup

This release:

- uses a much improved ("`gpt-v2`") prompt. Among other things, the prompt offers a tool function that allows the LLM dynamically request additional context about the source code;
- includes full JSON dump of exchanges in log files;
- provides a tool module, `coverup.logreader`, that reorganizes events in log files, so that full sequences for each code segment can be viewed in order;
- renames `--source-dir` to `--package-dir`, to better indicate what it does;
- improves interactions with `pytest-cleanslate`;
- makes the `Prompter` interface more flexible, allowing for more customization;

This release:
- renames `--source-dir` to `--module-dir`, to clarify that it should be the directory holding the module's sources;
- shows the before and after coverage relative to the source files requested, if any;
- fixes authentication error handling;
- switches to also using [pytest-cleanslate](https://github.com/plasma-umass/pytest-cleanslate) for disabling polluting tests;
- fixes GPTv1 and Claude prompts not using filenames relative to the Python path, causing some LLMs to generate `import` statements starting with "lib" or "src";
- fixes a bug not ignoring `import __main__` while detecting unavailable imports;

This release:
- switches to using the faster (and much cheapter) GPT4o model by default;
- greatly improves test isolation support, which now resides in `pytest-cleanslate`;

- added support for Anthropic, Bedrock and Ollama models, using `litellm`;
- added `--prompt-family` to select between prompt styles/versions;
- separated prompts into more easily modifiable module;
- implemented test collection isolation and changed to using it by default;
- various improvements to "bad test" finder;
- various adjustments to the prompts;
- implemented asynchronous test running and coverage collection;
- various bug fixes;
- improved packaging, so that project description shows properly on PyPI;

Just a quick bugfix release.

Bringing out a first, very early, release of CoverUp. Yay!