Improve highlighting structure

- switched to a sparse delta based map
- true lazy-loading to avoid any unneccessary allocations
- fixed windows management api

README.md

@@ -134,6 +134,7 @@ crib ./filename.ext
 ```
 
 *If `filename.ext` does not exist, it will be created*<br>
+*memory usage is average case 10MB + 2x size of file*<br>
 
 ## Keybindings