Search class to wrap internal data

[Fuad-HH]

As a continuation of standardizing the search method (next steps of #143), this wraps the search related particle state arrays inside this class. It includes the following tasks:

• [x] Create ParticleTracer class
• [x] Write test case
• [x] Add consequent search in the test case
• [x] remove finishedUnmoved
• [x] Move particle_done out as a parameter
• [ ] Make maxLoop a variable in ParticleTracer class
• [ ] Add a test case with GMSH mesh to test node orientation check or correction
• [ ] Rename trace_particle_through_mesh function parameters
• [ ] Clean up: hardcoded parameters, comments, etc.

[Fuad-HH]

@jacobmerson, Could you please take a look? Does the class look like you suggested?