Fix for GitHub issue #377

[auerswal]

This pull request has two commits:

1. Additional tests for useful features of the current code that reads target names from file (or standard input).
2. A fix for the reported issue, i.e., splitting long lines, and not supporting long, but possibly valid, DNS names.

[coveralls]

coverage: 87.692% (+0.08%) from 87.611%
when pulling ff1aa04 on auerswal:issue377
into 511aa37 on schweikert:develop.

[auerswal]

There are at least two bugs still lurking in the new code. I plan to add the test cases below, and fix the behavior. For now, I have converted the pull request to a "draft".

When the first part of the line read into the buffer ends with the target name, and the first character of the second part of the line is a '#', then the data from the second line part is ignored instead of added to the target name.

Observed behavior:

$ perl -e 'for (my $i = 1; $i < 4; $i++) { print " "x(255-11+$i)."127.0.0.$i#host.name.invalid\n" }' | ./src/fping 
127.0.0.1#host.name.invalid: Name or service not known
127.0.0.3#host.name.invalid: Name or service not known
127.0.0.2 is alive

Expected behavior:

$ perl -e 'for (my $i = 1; $i < 4; $i++) { print " "x(255-11+$i)."127.0.0.$i#host.name.invalid\n" }' | ./src/fping 
127.0.0.1#host.name.invalid: Name or service not known
127.0.0.2#host.name.invalid: Name or service not known
127.0.0.3#host.name.invalid: Name or service not known

Then there is the problem that a comment in the first part of the line still results in splitting long lines.

Observed behavior:

$ perl -e 'print "#"." "x300 ."localhost\n"' | ./src/fping 
localhost is alive

Expected behavior:

$ perl -e 'print "#"." "x300 ."localhost\n"' | ./src/fping