Consolidate SolverTerminationType enum.

1. Rename SolverTerminationType to TerminationType.
2. Consolidate the enum as
  a. CONVERGENCE - subsumes FUNCTION_TOLERANCE, PARAMETER_TOLERANCE and GRADIENT_TOLERANCE
  b. NO_CONVERGENCE
  c. FAILURE - captures all kinds of failures including DID_NOT_RUN.
  d. USER_SUCCESS
  e. USER_FAILURE
3. Solver::Summary::error is renamed to be Solver::Summary::message, to both
reduce confusion as well as capture its true meaning.

Change-Id: I27a382e66e67f5a4750d0ee914d941f6b53c326d
diff --git a/internal/ceres/covariance_test.cc b/internal/ceres/covariance_test.cc
index f3a5051..4680244 100644
--- a/internal/ceres/covariance_test.cc
+++ b/internal/ceres/covariance_test.cc
@@ -727,7 +727,7 @@
                                                       parameter_block_size_,
                                                       jacobian.data()),
                                 NULL,
-                                block_i );
+                                block_i);
       for (int j = i; j < num_parameter_blocks_; ++j) {
         double* block_j = parameters_.get() + j * parameter_block_size_;
         all_covariance_blocks_.push_back(make_pair(block_i, block_j));