#47 Multithreaded tests
#47 Code refactoring

Refactored BenchmarkBase class and extracted:
- IBenchmark which represents benchmark
- IBenchmarkRunner which runs both singlethreaded and multithreaded benchmark for the given container and benchmark
- IBenchmarkMeasurer which measures the benchmark

Removed verification logic from benchmark classes. It should be in container adapters unit tests. Tests need to be added.
Added build results and nuget packages directory to .gitignore
#47 Added an example of adapter tests
Merge branch 'issue47_Refactoring' of https://github.com/alexandrnikitin/IocPerformance into issue47
Merge branch 'issue47'
Updated DryIoc, Grace and StructureMap