Merge pull request #3 from adhishm/README_correctMoreTypos

Corrected Matryushka to Matryoshka in README.md
Merge branch 'version_0.0_simulateSingleSlipPlane_StrongInheritance' of github.com:adhishm/dd2d_Matryoshka into version_0.0_simulateSingleSlipPlane_StrongInheritance
This branch aims to convert the data structures to strongly inherited structures.
They will also be simpler. For example, a slip plane will have only a list of defects.
These defects can be child classes of Defect.