Slow interactions under medium-size profiles

[javierluraschi]

Medium-size profiles are taking long to load, drag the slider, and switch back to flame-graph view. I don't think this is a regression.

See: http://rpubs.com/jluraschi/profiler-sparklyr-test

For tab switching, the bottleneck seems to be constructing the SVG, there is a Forced reflow warning while getting a profile of the profile:

[Fuco1]

Is there a way to generate the profile without the bottom part. I honestly have no idea how to use it. My profile file is 45 megabytes and I only use the top part where the code is shown.

[hadley]

Duplicate of #104