"sar -o" now collects all possible statistics

sar now collects all possible statistics (including partitions ones)
when data are saved into a file with option -o ("sar -o" calls sadc
with option "-S XALL" instead of "-S ALL").
Small fix in sadc manual page about optional activities

Activities which are not collected by sadc by default are not limited to
interrupts and devices statistics. So update sadc manual page
accordingly.