feat: creating new mx_ suite of macros!

also adding new mx_getcode macro

tests/base/mp_init.test.sas

@@ -0,0 +1,24 @@
+/**
+  @file
+  @brief Testing mp_gsubfile.sas macro
+
+  <h4> SAS Macros </h4>
+  @li mp_init.sas
+  @li mp_assert.sas
+
+**/
+
+/**
+  * Test 1 - mp_init.sas actually already ran as part of testinit
+  * So lets test to make sure it will not run again
+  */
+
+%let initial_value=&sasjs_init_num;
+
+%mp_init()
+
+%mp_assert(
+  iftrue=("&initial_value"="&sasjs_init_num"),
+  desc=Check that mp_init() did not run twice,
+  outds=work.test_results
+)