sPuReMD: refactor and clean up preconditioner application code (level scheduling, graph coloring, Jacobi iteration). Conditionally change charge matrix for setting up preconditioner for ICHOLT and ILU(T).

sPuReMD: fix issue with graph coloring causing sporadic failures in solver convergence for EE and ACKS2. Conditionally change the charge matrix for ICHOLT and ILU(T) preconditioning. Refactor graph coloring code.

sPuReMD: remove force tabulation for charge matrices. Revise list references to mirror MPI code. Revert GMRES iteration counter.

sPuReMD: fix GMRES bug introduced from previous refactoring. Explicitly link OpenMP for library. Refactoring to remove global variables. Remove unnecessary OpenMP barriers after single regions.

sPuReMD: fixes to remove compilatoin warnings. Replace standard library functions with safer versions to avoid buffer overruns. Safer use of placeholders in format strings for printing.

sPuReMD: fix bug in GMRES where vector inputs and outputs to apply_preconditioner were being overwritten. Refactor OpenMP code in GMRES.

sPuReMD: split into library and driver for, e.g., optimization integration. Fix bug with interaction lists being allocated for hydrogen bonds when no hydorgen atoms present. Fix minimum allocation size of 3-body lists (uncovered with small lithium geometries). Refactor naming of conflicting data structures. Update .gitignore.

sPuReMD: remove unnecessary explicit OpenMP barriers. Conditionally enable OpenMP linear algebra code. Other general refactoring.

sPuReMD: add safe memory allocation functions. Fix issue with certain parameters for shielded van der Waals interactions not being correctly initialized. Other general refactoring.

sPuReMD: fix linear solver to work with no preconditioner. Fix issue when precondition recomputation frequency is zero. Other misc. changes.

sPuReMD: enable debug builds. Fix compilation issues when optimizations disabled (-O0). Fix graph coloring data structure management.

sPuReMD: complete preconditioner application using level scheduling with permutations based on graph coloring.