main: allow more comments from stdin input

Make sure that whitespace gets stripped from targets with comments,
when read from stdin. Allow comments to appear after targets on same
line when read from stdin.
ui: "in-line" display mode, without clearscreen

Attempt to display xping results without clearing screen using relative
cursor positioning.

The problem with relative positioning using "position save" codes
is that the save position appears "tainted" when the terminal gets
resized. Instead we keep track on our current line number and use the
"bottom" of our output as reference point. When redrawing move up number
of row corresponding to our current cursor row.

Output rows is number of targets plus padding for title and legend.

Additionally try to disable line wrapping to xping lines to scroll
unintenntionally to history.
main: require two-step, i.e. make && make install

version.o got rebuilt with every "make install". It should only rebuild
with every xping linking. This has the side effect of requiring make be
called for the components to be installed.
main: update uthash and switch to utlist

Switched from queue.h to utlist.h and
updated uthash and utlist to version 1.9.7.

Removed ping.c previously used for reference.