Created inventory control skeleton

Closes #139

[x] I have ensured that my commit message contains the Issue ID.
[x] I have ensured that my commit message contains the feature/bugfix description.
[ ] I have updated the documentation accordingly.
[x] I have ensured my code follows the coding guidelines.
[x] I have ran lint in my code locally prior to submission.
[x] I have built my changes in local successfully.
[x] I have added tests to cover my changes.
[x] All new and existing tests passed.

pointonsoftware / pscore