New: Added eol-last rule (Fixes #996)

`on` perf:

```
CPU Speed is 2261 with multiplier 7500000
Performance Run #1:  2853.71584ms
Performance Run #2:  2879.87336ms
Performance Run #3:  2856.63708ms
Performance Run #4:  2879.23096ms
Performance Run #5:  2874.884919ms
Performance budget ok:  2874.884919ms (limit: 3317.1163202122952ms)
```
`off` perf:

```
CPU Speed is 2261 with multiplier 7500000
Performance Run #1:  2863.81108ms
Performance Run #2:  2892.5836ms
Performance Run #3:  2906.70604ms
Performance Run #4:  2866.610639ms
Performance Run #5:  2897.305481ms
Performance budget ok:  2892.5836ms (limit: 3317.1163202122952ms)
```

You can just call `context.getSource()` (no arguments returns all the text)