quake-map 0.6.1

## Changelog

### 0.6.1

* Change documentation to require `Quake2SurfaceExtension::is_zeroed()` to
return false if `surface_value` is NaN

### 0.6.0

* Make `Q2SurfaceExtension` public

* Rename `WriteAttempt` to `WriteResult`

* Make Err variant of `ValidationResult` implement `core::error::Error` trait

### 0.5.2

* More README fixes (:

### 0.5.1

* Fix changelog and README

### 0.5.0

* Split quake-map off from quake-util

* Factor out confusing ext trait (no ".leak()")

* Misc. optimizations and refactoring