Mark tile indices as potentially unused
Rename test thorns to avoid conflicts
RunTests.m: Add Tiling script
Add regression test thorn repository as a submodule
Add grammar for interface.ccl
Add a general "Files" key to the Code object

Files are specified by name and content, and they are created in the thorn when it is generated.
Count operations in calculations and report them in a generated file in the doc directory

This is currently performed unconditionally
Refactor operation counting code into a new OperationCount.m file
Correct test for operation counts
Add CountOperations option to CountOperations test
Make operation counting optional
Update TestThorns submodule
Produce an error message if a scalar is used with indices
Merge branch 'master' into xTensor
Make KrancBasis public so that basis are printed in a nicer way
Identify symmetry-related components at the time a tensor is defined

Also fix an error in flattening out the components
Add a MatrixInverse function
Update TensorTools tests to use xTensor instead
Only define sonstant symbols which haven't already been defined
Allow for single-character parameters