Extended EFTEMjLogTool.

To write log messages an instance of EFTEMjLogTool has to be created.
All messages are written to a local and a global message-buffer. The
global message-buffer is not jet used.
Modified SR_EELS_CorrectionPlugin and SR_EELS_CorrectionOnlyPlugin.

SR_EELS_CorrectionPlugin calls SR_EELS_CorrectionOnlyPlugin for final
processing. SR_EELS_CorrectionOnlyPlugin has to be modified for this
purpose.

SR_EELS_CorrectionOnlyPlugin: I added all necessary comments.

SR_EELS_CorrectionPlugin: I optimised the manual mode.