Add -browse flag

[rakyll]

As a follow-up from #180, we want to be able to give the users a convenient way to start a new HTTP server at localhost:<random_port>.

There seems to be no good way to do it without a new flag. Empty -http value is conflicting with the positional argument.

$ pprof -http profile.out

I propose us to add a new flag (e.g. browse) that starts a server locally at a random port and opens the page in the browser.

/cc @aalexand

[aalexand]

Actually, a bit of markup was lost in my comment changing its meaning. What I typed was Maybe it would be a bit more convenient if we treated -http as "localhost:<port>" when just "<port>" is specified. Just that.

[rakyll]

Ugh, got you wrong.

It currently works if you just pass ":port". I think that's already good enough. I will fix the docs to document it. Happy to hear if you think supporting "port" is also valuable, but I prefer to require a colon for consistency.

[aalexand]

I agree, we can say it's WAI for now.

[rakyll]

Opened #204.

I am going to close this issue, please reopen if more convenience is needed at the cost of a new flag.