Fixed an '#if PERL_IMPLICIT_CONTEXT'.. Added link to explanatory comment. Added Changes.
Add pf (platform) files to MANIFEST, plus .travis.yml
Fix to write platforms test files to the temporary test output directory
Add perl 5.8, 5.18 and 5.19 to .travis.yml
Refactor some nytprofcalls internals. No functional changes.
Refactor Time::HiRes support so it can be enabled independently