ram usage is wrong with free

[emmanuelvargasiress]

Hello

thanks for this plugin ;)
just to mention on linux the calculation of the mem percent is wrong on linux host:

             total       used       free     shared    buffers     cached
Mem:         32114      29568       2546        680       1017      25988
-/+ buffers/cache:       2561      29552
Swap:        15258         25      15233

in the current calculation you are using only the "Mem" line but you need to use the "-/+ buffers/cache:" line to calculate the "real" memory usage

"free -/+ buffers/cache * 100 / Mem Total"
(in the example above : 29552 * 100 / 32114)

Thanks