Adding table of contents for Readme file

[schatekar]

The contents of the readme file are quite huge. It usually takes lot of scrolling around and lot of Ctrl+F's to find the stuff you are looking for. I thought a clickable table of contents would be a good start to better manage the documentation.

[pluma]

Good idea but some of the links are broken (reamde.md and readme.md instead of README.md).

This is actually pretty straightforward for me to add directly.

[pluma]

Thanks for the effort but it was easier to generate this from scratch (using Sublime Text literally just a few key strokes) than to refactor the PR. Please don't let this discourage you from contributing in the future.

[schatekar]

As long as you are generating something that will help with navigating through the huge readme file. I am new to ArangoJs and need to refer to documentation frequently. And most of the times I do not know in which API or section of the document my answer lies.