profile: remove memProfileRate package var

This one always annoyed me, the profile rate belongs to the profile, not the package.
Merge pull request #14 from pkg/102-remove-memprofilerate-pkg-var

profile: remove memProfileRate package var
profile: added example using the flags package

A strawman to iterate from.
responding to review feedback
tweaks
Merge pull request #15 from pkg/103-flag-parsing-strawman

profile: added example using the flags package
fix example_test