Restored CHANGELOG.md and added v1.0.0

Author: jakeboone02

CHANGELOG.md

@@ -0,0 +1,33 @@
+## 1.0.0 (2021-02-11)
+
+- New build system ([tsdx](https://tsdx.io/))
+
+## 0.5.1 (2019-08-24)
+
+- Fixed README.md note about return values
+
+## 0.5.0 (2019-08-24)
+
+### Breaking change
+
+- Returns `NaN` for invalid inputs instead of `-1`
+
+### Bug fixes
+
+- Handles negative numbers properly (fixes [#3](https://github.com/jakeboone02/numeric-quantity/issues/3))
+
+## 0.4.2 (2019-08-23)
+
+- Rewritten with TypeScript
+
+## 0.3.2 (2018-09-21)
+
+## 0.3.1 (2015-07-16)
+
+## 0.3.0 (2015-07-16)
+
+## 0.1.2 (2015-03-20)
+
+## 0.1.1 (2015-03-19)
+
+## 0.1.0 (2015-03-18)