✨ BREAKING: Add ability to limit recent emoji shown (#1)

Instead of `-P` being a flag for showing history it has become an option
whose argument is the number of history entries to show, `-P 4`.

To mimic the old behavior use `-P 0`.

Added some test coverage for history functionality.

Fixes #1.

CHANGELOG.md

@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - Pass through return code 1 from selection tool
+- (!) Number of displayed recent emoji can be set with `-P` option. This replaces previous `-P`
+  history flag toggle. Use number to set amount of recent entries to display, `-P3`. To
+  completely hide history use `-P0`
 
 ### Changed