Misspelled and cosmetic fixes.
Terminate program after collecting data for X times.

This is another option to end the program. Instead of doing some math with time
counter, use a numeric counter. It can be combined with -i option too. Also,
time (-E) has precedence over numeric (-C).
Merge pull request #24 from eulerto/fixes

Misspelled and cosmetic fixes.
Merge pull request #25 from eulerto/counter

Terminate program after collecting data for X times.
Documentation update with the new -C option to pgcluu_collectd.