Initial work adding sub entry and return events to the event stream
Add some initial docs about the new call=1 option
Add output and input handlers for sub entry and return data.
Add call=1 to testing variants. Make env_influence report smarter.
add note to t/test51-enable.x about need for more tests
Use calls=2 to get entry events. Add depth to return events.

Also avoid core dump when profiling is disabled.
Fix u2time clock (ie Time::HiRes, used by Windows).

Eg http://www.cpantesters.org/cpan/report/b5538f6b-6bf5-1014-88ea-c1bba98f0fbf
fixup MANIFEST
update .gitignore
merge Changes from v4 branch
initial working nytprofcalls
Squashed 'FlameGraph/' content from commit d9407a8

git-subtree-dir: FlameGraph
git-subtree-split: d9407a85935346b3ea8e0815e1856dfc861d8fce
Merge commit '8a0ed6170c6eae8f97b363d8b2a2fb6794b1bb41' as 'FlameGraph'
Add FlameGraph/... to MANIFEST
Cleanups for nytprofcalls
working but somewhat inefficient/bloated on big files
first step towards reusing the hashtable code
another step towards reusing the hashtable code
another step towards reusing the hashtable code
work in progress on nytprofcalls