Commented out key in NeXus dictionary for POLDI

Key for proton monitor is not present in sample files, so it should not
be read.
Grouping workspaces created during POLDI analysis per sample
Merge remote-tracking branch 'upstream/master'
Changed name of POLDI WorkspaceGroup

Having the same name for the grouped workspaces as for the raw data
resulted in segmentation faults.
Added code to represent POLDI's detector in an abstract way
Added license blocks to header files
Added centralElement to Detector
Added detector factory for POLDI
Started integrating detector code into autocorrelate
Fixed vector sizes in autocorrelation method

Since vector size will not change, the correct size is allocated
directly at construction.
Creating vectors with data for good wire only in PoldiAutoCorrelation5
Revert "Creating vectors with data for good wire only in PoldiAutoCorrelation5"

This reverts commit 612b15d4ecf3b3156d1525cb3495990f0afd77bf.
Revert "Fixed vector sizes in autocorrelation method"

This reverts commit 765accfeb11da2d7ad84c982d9965baca44fc1d5.
Fixed vector sizes in autocorrelation method

Since vector size will not change, the correct size is allocated
directly at construction.
Creating vectors with data for good wire only in PoldiAutoCorrelation5
Added POLDI chopper representation

It follows the same principle as the detector representation, providing
an interface that can be implemented in different ways if the chopper
should ever change.
Some small comment corrections in POLDI classes
Changed exception handling in PoldiBasicChopper to conform with
PoldiHeliumDetector
Started encapsulating auto-correlation algorithm

The auto-correlation algorithm will be "hidden" from the
PoldiAutoCorrelation-routine that is visible to users. The purpose of
this is to make all steps of the algorithm testable.
Merge remote-tracking branch 'upstream/master'