v0.0.3

Add HTTP timeout

v0.0.2

Rename project

v0.0.1: Support nested metrics and proxy mode (#1)

## Nested metrics support

For example expvars from
[datadog-agent](https://docs.datadoghq.com/integrations/agent_metrics/)

```json
{
    "logs-agent": {
        "BytesSent": 18481,
        "DestinationErrors": 0,
        "EncodedBytesSent": 1390,
        "HttpDestinationStats": {
            "container-images_9_reliable_0": {
                "idleMs": 0,
```

into

```
logs_agent_BytesSent 18481
logs_agent_DestinationErrors 0
logs_agent_EncodedBytesSent 1390
logs_agent_HttpDestinationStats_container_images_9_reliable_0_idleMs 0
```

## Proxy mode

Pass the proxy parameter e.g. `-proxy 127.0.0.1:8000` to run as a HTTP
proxy that translates responses from Go expvars to Prometheus metrics
format.

Tested Prometheus scraping with proxy_url.

Configuration for metrics is not applied at the moment.