Added support for simulated/embedded gprof output

[DepthDeluxe]

• This format is seen in simulation of certain embedded systems.

• This format does not include a time column and contains an additional measurement units column underneath (see line 89 of included example).

• Provided example and test in tests/prof/embedded.prof.

The source used to generate this embedded.prof profiling report is included below.

#include <stdio.h>

namespace helloworld {
void hello() {
  printf("hello");
}
void world() {
  printf(" world!\n");
}
void run(int iterations) {
  if (iterations % 2 == 0) {
    hello();
  } else {
    world();
  }
}
} // namespace helloworld

int main(int argc, char* arvg[]) {
  for (int i = 0; i < 100*1000; ++i) {
    helloworld::run(i);
  }
}

[codecov]

Codecov Report

Merging #86 (bcb1b85) into master (cdeea9e) will increase coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #86      +/-   ##
==========================================
+ Coverage   86.98%   87.03%   +0.04%     
==========================================
  Files           1        1              
  Lines        2229     2229              
==========================================
+ Hits         1939     1940       +1     
+ Misses        290      289       -1     

Files	Coverage Δ
gprof2dot.py	87.03% <ø> (+0.04%)	⬆️

[jrfonseca]

Looks great. Thank you.