Improve seed file reader

[MichaelRoeder]

Description

As a user, I would like to provide additional information for seed files, e.g., the type of a URI or some other data that could improve its processing. Therefore, the reader for the seed file should be improved to be able to process this additional information.

Solution

• To keep the solution general, it would be good if the reader would accept a CSV file with a head line which defines the keys for the values. In the following example uri is used to mark the column with the URIs while the other columns contain additional data which should be added to the URIs object.

  "uri","key1","key2"
  "http://example1.org","value1-1","value1-2"
  "http://example2.org","","value2-2"
  "http://example3.org",,

• Note that "" should be used as an empty value, i.e., the key should be added with an empty string as value.
• Note that the key value pair (or the key with an empty value) should only be added if the cell is not empty. The line of "http://example3.org" contains two empty cells which should make sure that both keys are not added to this URI.

[MichaelRoeder]

Add a JUnit test for this seed file reader and close #14 after that.

[gsjunior86]

pushed on develop branch