Added automation for Samples which are non-Revit based.

<h4>Summary</h4>
I have added few Samples to **DynamoRevitTests** project because those were dependent on Revit. Remaining Samples I am adding in **WorkflowTest** project which are non-Revit based. Most of them are generating Geometry. 
<h4>Changes</h4>
- Created new class **DynamoSamples** in WorkFlowTests Project. 
- Created two more functions (OpenSampleModel, GetSampleDirectory()) to access original Samples from their folder on git.
- Few Samples splitted in multiple test cases to keep the debugging easy.
<h4>Reviwer</h4>
@ikeough @lukechurch @Randy-ma

**Note:** All tests are passing on latest build
![image](https://cloud.githubusercontent.com/assets/5109531/3610993/b701227a-0d94-11e4-9e96-613de4072489.png)

Added this method to get Sample directory.