Make height option work under Windows (#1341)

Separate Unix & Windows code into platform specific files for light renderer

CHANGELOG.md

@@ -9,6 +9,7 @@ CHANGELOG
       finder instead of printing horizontal lines above and below it.
       The previous style is available via `--border=horizontal`
 - Added `--pointer` and `--marker` options
+- `--height` option is now available on Windows binary (@kelleyma49)
 - More keys and actions for `--bind`
 - Bug fixes and improvements
 - Vim plugin: Floating windows support