fix code style:
- tabs vs spaces 4 (psr)
- doc
- max line length (psr)
fix coding standard:
- spaces
- braces
- line length
fix typo
add a invalid json and empty response
fix json response error
Merge pull request #3 from ClemensSahs/hotfix/sistrix-wip2

Hotfix/sistrix wip2 merged, thanks!