Use int32 for parameter block sizes.

CostFunction now uses int32 instead of int16
to store the size of its parameter blocks.

This is an API breaking change.

Change-Id: I032ea583bc7ea4b3009be25d23a3be143749c73e
diff --git a/internal/ceres/covariance_test.cc b/internal/ceres/covariance_test.cc
index 4680244..471b223 100644
--- a/internal/ceres/covariance_test.cc
+++ b/internal/ceres/covariance_test.cc
@@ -125,7 +125,7 @@
 class UnaryCostFunction: public CostFunction {
  public:
   UnaryCostFunction(const int num_residuals,
-                    const int16 parameter_block_size,
+                    const int32 parameter_block_size,
                     const double* jacobian)
       : jacobian_(jacobian, jacobian + num_residuals * parameter_block_size) {
     set_num_residuals(num_residuals);
@@ -158,8 +158,8 @@
 class BinaryCostFunction: public CostFunction {
  public:
   BinaryCostFunction(const int num_residuals,
-                     const int16 parameter_block1_size,
-                     const int16 parameter_block2_size,
+                     const int32 parameter_block1_size,
+                     const int32 parameter_block2_size,
                      const double* jacobian1,
                      const double* jacobian2)
       : jacobian1_(jacobian1,