Merge branch 'efiapi' into 'master'

Use efiapi for entry point

See merge request !5

src/lib.rs

 #![no_std]
+#![feature(abi_efiapi)]
 #![feature(asm)]
 #![feature(concat_idents)]
 #![feature(core_intrinsics)]

src/rt/start.rs

@@ -3,7 +3,7 @@ use uefi::status::Status;
 use uefi::system::SystemTable;
 
 #[no_mangle]
-pub unsafe extern "win64" fn efi_main(handle: Handle, system_table: &'static mut SystemTable) -> Status {
+pub unsafe extern "efiapi" fn efi_main(handle: Handle, system_table: &'static mut SystemTable) -> Status {
     extern "C" {
         fn main() -> Status;
     }