Affects Version/s: libdiscid 0.2.2, libdiscid 0.5.1
Fix Version/s: libdiscid 0.6.0
When not having done a read() or put() some attributes like the ID have undefined behavior.
For discid_get_id() we have an assertion in debug builds and return NULL in release/normal builds.
We shouldn't have assertion errors in anything the user can produce (debug build or not) when we can recover normally.
Returning the empty string is an option in this case.
At lest the current behavior should be mentioned in the documentation.