rebase: rebased onto master

Author: o-murphy

py_ballisticcalc.exts/py_ballisticcalc_exts/rk45_engine.pxd

@@ -1,7 +1,7 @@
 # pxd for rk4_engine to expose CythonizedRK4IntegrationEngine
 from py_ballisticcalc_exts.base_types cimport BCLIBC_TerminationReason
 from py_ballisticcalc_exts.base_engine cimport (
-    BCLIBC_Engine,
+    BCLIBC_BaseEngine,
     CythonizedBaseIntegrationEngine,
     BCLIBC_BaseTrajDataHandlerInterface,
 )
@@ -10,7 +10,7 @@ from py_ballisticcalc_exts.base_engine cimport (
 cdef extern from "include/bclibc/rk45.hpp" namespace "bclibc" nogil:
 
     void BCLIBC_integrateRK45(
-        BCLIBC_Engine &eng,
+        BCLIBC_BaseEngine &eng,
         BCLIBC_BaseTrajDataHandlerInterface &handler,
         BCLIBC_TerminationReason &reason,
     ) except +

py_ballisticcalc.exts/py_ballisticcalc_exts/rk45_engine.pyx

@@ -6,8 +6,7 @@ Because storing each step in a BCLIBC_BaseTrajSeq is practically costless,
 we always run with "dense_output=True".
 """
 from cython cimport final
-from py_ballisticcalc_exts.base_engine cimport CythonizedBaseIntegrationEngine
-
+from py_ballisticcalc_exts.base_engine cimport CythonizedBaseIntegrationEngine, BCLIBC_IntegrateCallable
 
 __all__ = [
     'CythonizedRK45IntegrationEngine',
@@ -17,11 +16,7 @@ __all__ = [
 @final
 cdef class CythonizedRK45IntegrationEngine(CythonizedBaseIntegrationEngine):
     """Cythonized RK45 (Runge-Kutta 5th order) integration engine for ballistic calculations."""
-    DEFAULT_TIME_STEP = 0.0025
-
+    
     def __cinit__(self, object _config):
-        self._this.integrate_func_ptr = BCLIBC_integrateRK45
-
-    cdef double get_calc_step(CythonizedRK45IntegrationEngine self):
-        """Calculate the step size for integration."""
-        return self.DEFAULT_TIME_STEP * CythonizedBaseIntegrationEngine.get_calc_step(self)
+        self._DEFAULT_TIME_STEP = 0.0025
+        self._this.integrate_func = BCLIBC_IntegrateCallable(BCLIBC_integrateRK45)

py_ballisticcalc.exts/py_ballisticcalc_exts/src/rk45.cpp

@@ -44,7 +44,7 @@ namespace bclibc
     }
 
     void BCLIBC_integrateRK45(
-        BCLIBC_Engine &eng,
+        BCLIBC_BaseEngine &eng,
         BCLIBC_BaseTrajDataHandlerInterface &handler,
         BCLIBC_TerminationReason &reason)
     {