suite: improve output of request body in HTML report
suite: improve output of request body in HTML report

The old cleanup code was very strict and replace newlines (and tabs et al.) with the
Unicode replacement charater which is very strange when debugging a request:
A perfectly valid looking request body (e.g. for as SQL pseudo request) is
displayed with replacement charaters. This is neither helpful nor necessary.
A pre tag can display newlines and tabs without problems.

The new code keeps these tabs, newlines, etc. in the output. Stuff like 'real'
control charaters are now displayed in hexadeciaml escaping like '\xa' for BEL.
This should facialiate debugging broken rquests.

vdobler/ht,vdobler/ht,vdobler/ht,vdobler/ht