thoroughly document connection parameters

[kontrafiktion]

Issues #44 and #24 (and perhaps even #47) both have the same basic cause: missing documentation of the connection parameters in different scenarios.

What is working: using hostname, port and SID.

Is the name in tnsnames.ora also working? How would the parameters have to be set?

To reduce the number of issues, a more detailed documentation would really be great. I could try (by trial and error) to reverse engineer the possible values, but if someone with a more thorough kowledge of the code and the different connection paramters would step in, I would very much prefer that ...

[kontrafiktion]

Perhaps not thoroughly documented, but I think it's good enough.