The read method gets the whole file if no chunk_size specified.
Tests for read method of SwiftClientStorageFile.
Adds the chunks method to get a generator with chunk_size.
Updates the tests to consider the chunks and multiple_chunks methods from default Django File object API.
Merge remote-tracking branch 'upstream/master' into filelike-behavior
Merge pull request #91 from michelts/filelike-behavior

File like behavior for SwiftClientStorageFile