Add textual comparison to systemtests (WCS et al)

[abeccati]

I have failing test with output that differs only for the endline mode (Win vs Lin). Weird since I am using Lin but get output in Win mode.

A robust way of dealing with that would be to add a textual comparison mode to the existing image and byte.

In RASSRC/systemtest/util/common.sh add case for when file is text to compare using "diff -w" which ignores all whitespace during the comparison.

PS: wanted to assign to nkolev but cannot find him in the users drop down