Improve Description of ValueIO

[linuswagner]

Is your feature request related to a problem? Please describe. When I try to store variables in files and restore them using the ValueIO module, it is not clear to me, which methods to pair from write and read for this to work properly.

Describe the solution you'd like A few examples how to store and retrieve data using the ValueIO module would be nice to have.

[linuswagner]

I think, this is mostly a problem for the usage of readTextValueFileWithEmbeddedTypes. The binary versions work without much thinking for me