Now the gadget show EXACTLY the same values of the free command on my machine,
but note: I found at least 3 different implementation of procpc so your values could be a bit different.
It's hard to mimic "free" output parsing /proc/meminfo... we should really use sysinfo.h
directly (like free does).
btw, on my system now the values are really near the "free" output
* collect more info than just 2 percentage
* improve performance by parsing proc only onece every loop
* use active memory to calc percentage, now the value is near the other mem tools I have