Use 1-D interpolation for direct forcing.

* Earlier interpolation stencil was incorrect.
Smart plot extent in plotVelocity.py.
Modify a couple of scripts.

* Use str.format in cavityRe100.py.
* Add an exception to readData.py if run.info is missing.
Add script analyzeTags.py.

* Outputs the number of common forcing points across refined grids.
Edit tagPoints.inl, io.cu and scripts.

* Make flag true when grid point coincides with body in y-direction.
* Take solver tolerances as command line options.
* cavityRe100.py: change option names and accept tolerances as inputs.
* Use a single preceding hyphen for command line options.
Output the mask which tags all exterior points.

* Make tagPoints output the file mask.txt.
* Write function readMask to read and return the exterior points.
* cavityRe100.py now calculates convergence excluding interior points.
Check convergence of the direct forcing method.

* Add cases: Lid-driven cavity with a circle/rectangle at the center.
* Edit .gitignore.
* Add bodyFile quad.bdy to describe the rectangle.
Merge branch '1d-interpolation'