Allow "all" option, i.e. "exporters=all" (part of #78)
Allow "all" option, i.e. "exporters=all" (part of #78)

ig-sinicyn/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,alinasmirnova/BenchmarkDotNet,Teknikaali/BenchmarkDotNet,alinasmirnova/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,redknightlois/BenchmarkDotNet,ig-sinicyn/BenchmarkDotNet,redknightlois/BenchmarkDotNet,ig-sinicyn/BenchmarkDotNet,Ky7m/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,redknightlois/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,Teknikaali/BenchmarkDotNet,Ky7m/BenchmarkDotNet,Ky7m/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,alinasmirnova/BenchmarkDotNet,alinasmirnova/BenchmarkDotNet,Teknikaali/BenchmarkDotNet,PerfDotNet/BenchmarkDotNet,Ky7m/BenchmarkDotNet,adamsitnik/BenchmarkDotNet,ig-sinicyn/BenchmarkDotNet