various

Hi.

The difference from compressing the images is:

```
Filename                            Decrease (KB)
==================================================
forkme_right_darkblue_121621.png:   2.92
jshint-blue.png:                    8.23
jshint.png:                         7.7
==================================================
Sum:                                18.95
```

I didn't know if you prefer tabs for the md files, but spaces were mostly used there so I followed that. For the html files, tabs were used.

Let me know if you want any changes in the PR.