Complete transition to fn. Introduce global/threadlocal

resources/testproject/bar.c3

@@ -3,7 +3,7 @@ module bar;
 import baz::foo;
 import testbaz::zab;
 
-func void test()
+fn void test()
 {
     Foo x;
     baz::foo::test();

resources/testproject/foo.c3

@@ -7,14 +7,14 @@ struct Foo
     int a;
 }
 
-extern func void printf(char *hello);
+extern fn void printf(char *hello);
 
-private func void ofke()
+private fn void ofke()
 {}
 
-private func void exple() {}
+private fn void exple() {}
 
-func void test()
+fn void test()
 {
     printf("Hello from baz::foo::test()!\n");
 }

resources/testproject/hello_world.c3

@@ -1,9 +1,9 @@
 module hello_world;
 import bar;
 
-extern func void printf(char *hello);
+extern fn void printf(char *hello);
 
-func int main(int x)
+fn int main(int x)
 {
     printf("Hello World!\n");
     bar::test();