MDEventWorkspace does not export ExperimentInfo methods

[Gesner Passos]

When testing #5776, i tried to execute the following script in order to check the log data

Load(Filename='POLREF00004699.nxs',OutputWorkspace='POLREF00004699')
ConvertUnits(InputWorkspace='POLREF00004699',OutputWorkspace='inter_ws',Target='Wavelength',AlignBins='1')
ConvertSpectrumAxis(InputWorkspace='inter_ws',OutputWorkspace='inter_ws_theta',Target='signed_theta')
ConvertToReflectometryQ(InputWorkspace='inter_ws_theta',OutputDimensions='K (incident, final)',Extents='0,0.5,0,0.5',OutputWorkspace='inter_converted')
ws_initial = mtd['POLREF00004699_1']
ws_final = mtd['inter_converted_1']

first_log = ws_initial.run().getLogData()
second_log = ws_final.run().getLogData()

It fails, with the following message:

AttributeError: 'IMDEventWorkspace' object has no attribute 'run'
  at line 12 in ''

With the help of Owen, we found that the MDEventWorkspace declares inheiriting from MultipleExperimentInfos that does not export any method to python API -> PythonInterface/mantid/api/src/Exports/MultipleExperimentInfos.cpp

The unittest, Framework/MDEvents/test/ConvertToReflectometrQTest.h:test_execute suggests, for me, that MDEventWorkspace could export also experiment infos.

[Nick Draper]

Moved at the code freeze for release 2.4

[Michael Reuter]

Refs #6060. Python API call for multiple experiment infos.

Changeset: bfeb28b8d0488d9b7b21915d547cf00c6d81d57e

[Michael Reuter]

Refs #6060. Adding unit test.

Changeset: b22074f5e4dd8f3a0f6f7b10c9502a0339dbf9fe

[Michael Reuter]

To test: Run the code above but changing the last line to

second_log = ws_final.getExperimentInfo(0).run().getLogData()

[Stuart Campbell]

This ticket has been transferred to github issue ​6906