Change definition of summary/description break

In this commit I have made the following documentation changes:

- Changed short description to summary
- Changed long description to description
- Changed example mail address
- Changed definition when a summary breaks and becomes a description
  to match PSR-5 and actual usage.

See: https://github.com/phpDocumentor/ReflectionDocBlock/issues/34#issuecomment-49510977
The "e.g." should have quotes around it.

Without them, it looks like a spelling error - like you said (and erroneously wrote)
> such as for example a version number

whereas you mean
> such as "e.g.", a version number