Updates readme
0.1.5
Updates dependencies
Add a command for benchmark (CLI)
Reduce `usort` calls on EmitterTrait #13
Add --diagnose option to CLI #13

`bin/ciconia --diagnose --gfm README.md` will output:

```
+------------+----------------------------------------------------------+----------+-----------+
| Event | Callback | Duration | MEM Usage |
+------------+----------------------------------------------------------+----------+-----------+
| | render() | - | - |
| initialize | Core\WhitespaceExtension:initialize | 1 | 2621440 |
| detab | Core\WhitespaceExtension:detab | 0 | 2621440 |
| initialize | Gfm\FencedCodeBlockExtension:processFencedCodeBlock | 4 | 2621440 |
...snip
```
Add a link to gist 7443440
Remove unnecessary matching sub-pattern from regexp
v0.1.6
Confirm running `$ciconia->render()` multiple times will not break html.