The source project of this merge request has been removed.
Add support for MemAvailable
MemAvailable is in /proc/meminfo since Linux 3.14.
This aligns the reported memory usage with the memory usage reported by xfce4-systemload-plugin.
Not using MemAvailable in the task manager might lead some people to experience panel-plugins/xfce4-systemload-plugin#10 (closed) due to the difference in reported memory.
Please merge. Thanks.