rework: AST now uses an arena for allocation

For now it works but i dont really like that i use ParseResult, i mean
is necessary but i think i will try to make it cleaner so that i can
just directly use like parse and pass tath into evaluate, that would
require to move the main evaluate funciton into evaluate_tree or
something  and evaluate takes the arena, uses evaluate_tree and frees
the arena, will try that the next commit but for now this version works
perfectly.

test/CMakeLists.txt

@@ -3,6 +3,7 @@ find_package(cmocka REQUIRED)
 add_executable(test_nodeArray test_ASTNodeArray.c)
 add_executable(test_lexer test_lexer.c)
 add_executable(test_parser test_parser.c)
+add_executable(test_evaluator test_evaluator.c)
 
 target_link_libraries(test_nodeArray
     calculator_lib
@@ -19,6 +20,12 @@ target_link_libraries(test_parser
     cmocka::cmocka
 )
 
+target_link_libraries(test_evaluator
+    calculator_lib
+    cmocka::cmocka
+)
+
 add_test(NAME nodeArray_tests COMMAND test_nodeArray)
 add_test(NAME lexer_tests COMMAND test_lexer)
 add_test(NAME parser_tests COMMAND test_parser)
+add_test(NAME evaluator_tests COMMAND test_evaluator)