Revisit examples

[thijsmie]

We should revisit the examples, as several points of confusion exist about them and, in @eboasson's own words, they are not very good. A slight rewrite, and maybe a rename, because people don't realise they should not be using the roundtrip example to measure roundtrip and should not be using the throughput example to measure throughput. Some additional examples of common patterns would not be a bad idea either.

Tasks:

• [ ] Revisit helloworld
• [ ] Revisit listtopics
• [ ] Move perfscript, it is not an example, but mention it in readme
• [ ] Revisit and rename roundtrip
• [ ] Revisit and rename throughput
• [ ] Revisit and rename shm_throughput
• [ ] Migrate index.rst -> readme.md and all other readme.rst's to md

[JesseRengers]

@thijsmie out of curiosity: why shouldn´t you use the roundtrip and throughput examples to measure these quantities?

[thijsmie]

Hi @JesseRengers!

These examples are aimed at being somewhat readable and not present an optimal way to do these measurements. This is problematic when people use these examples to measure and compare about other technologies or DDS vendors.