use * for pointer type instead of &

See #770

To help automatically translate code, see the
zig-fmt-pointer-reform-2 branch.

This will convert all & into *. Due to the syntax
ambiguity (which is why we are making this change),
even address-of & will turn into *, so you'll have
to manually fix thes instances. You will be guaranteed
to get compile errors for them - expected 'type', found 'foo'

example/cat/main.zig

@@ -41,7 +41,7 @@ fn usage(exe: []const u8) !void {
     return error.Invalid;
 }
 
-fn cat_file(stdout: &os.File, file: &os.File) !void {
+fn cat_file(stdout: *os.File, file: *os.File) !void {
     var buf: [1024 * 4]u8 = undefined;
 
     while (true) {

example/hello_world/hello_libc.zig

@@ -7,7 +7,7 @@ const c = @cImport({
 
 const msg = c"Hello, world!\n";
 
-export fn main(argc: c_int, argv: &&u8) c_int {
+export fn main(argc: c_int, argv: **u8) c_int {
     if (c.printf(msg) != c_int(c.strlen(msg))) return -1;
 
     return 0;

example/mix_o_files/base64.zig

@@ -1,6 +1,6 @@
 const base64 = @import("std").base64;
 
-export fn decode_base_64(dest_ptr: &u8, dest_len: usize, source_ptr: &const u8, source_len: usize) usize {
+export fn decode_base_64(dest_ptr: *u8, dest_len: usize, source_ptr: *const u8, source_len: usize) usize {
     const src = source_ptr[0..source_len];
     const dest = dest_ptr[0..dest_len];
     const base64_decoder = base64.standard_decoder_unsafe;

example/mix_o_files/build.zig

@@ -1,6 +1,6 @@
 const Builder = @import("std").build.Builder;
 
-pub fn build(b: &Builder) void {
+pub fn build(b: *Builder) void {
     const obj = b.addObject("base64", "base64.zig");
 
     const exe = b.addCExecutable("test");

example/shared_library/build.zig

@@ -1,6 +1,6 @@
 const Builder = @import("std").build.Builder;
 
-pub fn build(b: &Builder) void {
+pub fn build(b: *Builder) void {
     const lib = b.addSharedLibrary("mathtest", "mathtest.zig", b.version(1, 0, 0));
 
     const exe = b.addCExecutable("test");