Each method now ontains a -FromReader counterpart
such that it'll allow use of those helper-methods
even when someone does not have his data in a physical
file. The original methods make use of those -FromReader
methods.
The reader is being reset (Seek(0, 0)) before every method-
specific read, to ensure it's reading from the start of the
reader.
Test cases are not yet touched, and I'm not sure they should.
