added multiple expression support for @bs macro, removed @bcomp. added common histogram axis. Fixes #8

[ajinkya-k]

This PR modifies the Base.show method for comparative benchmarking using @bcomp to display histograms with a common x-axis, making them histograms directly comparable. Also fixes #8

julia> @bs rand(500:1000) rand(_), rand(_^2)
Chairmarks.Benchmark: 336 samples with 1 evaluation.
 Range (min … max):  333.000 ns …   3.750 μs  ┊ GC (min … max): 0.00% … 0.00%
 Time  (median):     583.000 ns               ┊ GC (median):    0.00%
 Time  (mean ± σ):   607.896 ns ± 264.546 ns  ┊ GC (mean ± σ):  0.00% ± 0.00%

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  333 ns        Histogram: log(frequency) by time       2.44 ms <

 Memory estimate: 4.06 KiB, allocs estimate: 3.
Chairmarks.Benchmark: 336 samples with 1 evaluation.
 Range (min … max):  127.459 μs …   2.437 ms  ┊ GC (min … max): 0.00% … 82.74%
 Time  (median):     442.792 μs               ┊ GC (median):    0.00%
 Time  (mean ± σ):   495.488 μs ± 283.638 μs  ┊ GC (mean ± σ):  6.80% ± 16.97%

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  333 ns           Histogram: frequency by time         2.44 ms <

 Memory estimate: 1.92 MiB, allocs estimate: 3.

[ajinkya-k]

@astrozot There is one issue that I could not figure out how to solve: I am using print(io, "\n") (on line 324 in the code) to insert a new line between the prints for each individual benchmark, but this causes there to be two empty lines at the very end, one of which is added by default by the Julia REPL.

[astrozot]

Hi @ajinkya-k , thank you, I will take care of it.

[ajinkya-k]

@astrozot @LilithHafner can you try this out and see if you can find any edge cases or issues?

[ajinkya-k]

@astrozot does something else need to be done to merge this?

[ajinkya-k]

hey @astrozot did you get a chance to see this PR?

[astrozot]

Hi @ajinkya-k , sorry for the delay, but I am quite busy in this period and did not have a chance to check your code. Will try to do it soon.

[ajinkya-k]

@astrozot No worries. Sorry to bother you.