Redmine#1032 - makes readfile() more generic, able to read /proc, /sys files on Linux (based on Ted's work, insights from Bas)
Adding readfile() acceptance tests from Ted Zlatanov
Adding a file to readfile acceptance test, using 0 as maxsize for /proc and /sys files
Merge pull request #1041 from lpefferkorn/fix_cfreadfile

Redmine #1032 - makes readfile() more generic