Add socket count

[benjaminlebigot]

Hi,

Thanks for your work, we are using your library to retrieve hardware information which we use to estimate environmental impact of pools of servers. Your work has saved us a lot of time, thanks again.

Adding the socket count retrieved from /proc/cpuinfo.

A patch was needed on the functions: _get_field(), _get_field_actual() in order to retrieve the max value of a
given field.

Tests have been adapted and are all passing.

Don't hesitate to contact me for any further information or adaptation.

[workhorsy]

I'm trying to make py-cpuinfo work consistently on every platform (Linux/Windows/OSX/BeOS/Haiku/Solaris). This looks to only gets socket count on Linux. If I add the ability to get socket count, it needs to work consistently on every platform. Plus it looks like it uses curses, which I don't think works on every platform.