disabled menu password prompt cursor(issue #14)
supported initrdfs.

1. 支持读写initrdfs(cpio new format)内部文件.

   例子,访问initrd.gz文件里面的文件内容(可以查看修改哦)
   也可以利用这个来动态修改initrd的启动脚本实现一些特殊功能,当然了目前还是不能改变文件大小.
   map /inirtd.gz (rd)
   ls (rd)/

2. initrd 多个文件时可以生成cpio new格式.
   initrd @name=FILE @name1=FILE1

   如下例子可以通过[WIMBOOT](http://ipxe.org/wimboot)启动WIM文件

   kernel /wimboot
   initrd @bcd=/boot/bcd @boot.sdi=/boot/boot.sdi @bootmgr=/boot/bootmgr @boot.wim=/boot/boot.wim
支持直访问某个内存区域(md,BASE,SIZE),以字节为单位.

比如在内存块0x887700长度0x51200是一个软盘镜像,则可以使用如下方式快速访问

ls (md,0x887700,0x51200)/

如果是硬盘镜像,也可以直接访问硬盘分区.
ls (md,0x887700,0x51200,0)/
add autogen/bootstrap

* This makes it more convenient to invoke autotools. Also MinGW users
  may need to run one of these scripts to be able to compile.
enable silent rules when building

* Note: ONLY configure.ac and stage2/Makefile.am were manually modified.
  The other files were generated by autotools.
fix assembler warnings

* dosstart.S:1356: Warning: using `%ax' instead of `%eax' due to `w' suffix
* grldrstart.S:1277: Warning: using `%ax' instead of `%eax' due to `w' suffix
fix 2 compiler warnings

* char_io.c:283:7: warning: pointer targets in assignment differ in signedness
* fsys_initrd.c:56:13: warning: initialization makes pointer from integer without a cast
fix assembler warnings
修正(md,BASE,SIZE)的BUG

delmod -l XXX 改成返回该模块所在内存的起始位置.
fix md device access issues
fix map_func bug
fix MinGW build

* Use the SIZEOF() macro in ldscript, to find if a section is empty or not defined.
* Ensure that -fno-asynchronous-unwind-tables is used when checking objcopy behaviour,
  by setting CPPFLAGS in configure.ac. Without this, the objcopy absolute address test
  fails because gcc on MinGW creates a .eh_frame section, that objcopy can't handle.
* Note: To get a working grub4dos using MinGW, you may have to downgrade gcc to 4.6.2 using:
     mingw-get upgrade gcc=4.6.2-1
     mingw-get install mpc=0.8.1-1
  You should also run autogen.sh or bootstrap.sh before invoking configure.
(tinybit) fix a bug that erroneously hooked/unhooked non-fb drives.
Update readme doc
Fix Makefile bug in 0.4.6a

修改由于 cc53a00 版本的改动导致grldr_cd.bin和grldr.pbr生成错误的问题.
﻿Fix build bug in 0.4.6a