Regression test Mask-1 fails

The Mask-1 regression test fails after merging (src!633 (merged)) by small differences with respect to the reference values:

	 Checksum for reference Mask-1.stat.md5 OK 
	 Checksum for reference Mask-1.out.md5 OK 
	 Checksum for reference Mask-1.lbal.md5 OK 
Run regression test Mask-1
Test rms_x(last) failed: 4.829711787474912e-06 (eps=2e-08) 
Test rms_y(last) failed: 1.6291845585723712e-06 (eps=2e-08) 
Test rms_s(last) failed: 9.365723447670588e-07 (eps=2e-08) 
Test energy(last) failed: 0.00029003990081832853 (eps=2e-08) 
Test numParticles(last) failed: 8.0 (eps=2e-08) 

The reference solution of Mask-1 has to be updated