Avoid file read when TET_RULESET is set
When the TET_RULESET macro is set, UGGrid reads the ASCII file RefRules.data from disk, which contains a long list of refinement rules (about 10000 lines long). This is inconvenient, because user programs crash if the file is not in the correct location. It can also hurt performance in a large-scale distributed setting. We should find a way to compile the refinement rules table into the library.