Add more comprehensive support for compare operators

[monstermichl]

I tried to use the converter but ran into problems with if-compare-operators, so I extended it. Additionally, I removed the first space after the command expansion because the leading space can lead to problems in further comparisons.

Before accepting the pull-request, please make sure that everything works as expected. Even though I added tests that passed and checked the correct functionality with the following script, you might have some additional tests to make sure, this changes don't break anything.

if [ 1 == 1 ]; then echo 1; fi
if [ 1 != 2 ]; then echo 2; fi
if [ "hello" != "world" ]; then echo 3; fi
if [ ! "hello" == "world" ]; then echo 4; fi
if [ 1 -lt 2 ]; then echo 5; fi
if [ 2 -le 2 ]; then echo 6; fi
if [ 2 -eq 2 ]; then echo 7; fi
if [ 3 -ge 2 ]; then echo 8; fi
if [ 3 -gt 2 ]; then echo 9; fi
if [ "hello" -ne "world" ]; then echo 10; fi
if [ "hello" -eq "hello" ]; then echo 11; fi

[daniel-sc]

Hi @monstermichl - thanks for the contribution!!
I'm not sure I understand if the added :~1 works in all cases, but I guess it makes some sense :)

[monstermichl]

I hope it works in all cases, but I think since each run of the FOR-loop adds a space in front, removing the first one afterwards should be fine :)