Reorganize README and correct some English errors.

README.md

@@ -2,38 +2,52 @@
 
 [![Build Status](https://travis-ci.org/snmsts/roswell.svg?branch=master)](https://travis-ci.org/snmsts/roswell)
 
-This software is now beta.Basic interfaces are fixed.I beleive it works well on some platform,
-but some part are not implemented,not stable on other os yet.
+This software is still beta. Basic interfaces are fixed, we beleive it works well on Unix-like platforms like Linux, Mac OS X and FreeBSD, but some parts are not implemented, not stable on other OSes yet.
 
 ## Description
-Installing Common Lisp and setting up everything just work is still difficult and you have to learn some tips.
+Roswell is a command line tool to install and manage Common Lisp implementations damn easily.
 
-## Why we named roswell?
-From ‘[made with secret alien technology](http://www.lisperati.com/logo.html)’.
+## Limitations
+There's a lot of works should be done.
 
-I felt making it easier to use Lisp for people is a kind of making opportunity for humanbeings to mingle with alien technology. I recall ‘roswell incident’ by the concept. I'm not sure what you feel.
+- [SBCL](http://sbcl.org/) is the only one we supports currently ([#9](https://github.com/snmsts/roswell/issues/9))
+- Not supports Windows (working on at [#1](https://github.com/snmsts/roswell/issues/1))
 
 ## Installation
 
+### Building
+
+#### For Mac OS X users
+
+If you're on Mac OS X and wanna use Homebrew, use the custom tap:
+
+    $ brew tap snmsts/roswell
+    $ brew install roswell
+
+#### From source code
+
     $ git clone -b release https://github.com/snmsts/roswell.git
+    $ cd roswell
     $ sh bootstrap
     $ ./configure
     $ make
     $ sudo make install
 
-## How to use
-### setting up
-First of all, you have to install Lisp environment. You can install a binary version of SBCL and Quicklisp from internet by these commands:
+### Setup
+
+First of all, you have to install Lisp environment. You can install a binary version of SBCL and Quicklisp from internet by this command:
 
     $ ros setup
 
-### command help
-After the installation type ros and you'll get some information by
+After the installation, you can get sub-commands and command line options by this command:
 
     $ ros
 
-### install lisp
-If you want to install the newest released version of sbcl you can do it by
+## How to use
+
+### Installing Lisps
+
+If you want to install the newest released version of sbcl you can do it by:
 
     $ ros install sbcl
 
@@ -43,32 +57,33 @@ and if you have specific version like "1.2.0" to install then
 
 will install that version.
 
-### set default implementation used by roswell.
+You can get which version of SBCL are installed by this command:
 
     $ ros list installed sbcl
 
-will return which version of sbcl are installed.
-
-then
+### Setting the default implementation used by ros
 
     $ ros run -- --version
 
-will show you which version are used.You can change implementation by
+will show you which version are used. You can change implementation by
 
     $ ros use sbcl/1.2.3
 
-## Using roswell in Emacs and SLIME
-to setup slime with roswell,type like this
+## Using roswell with Emacs and SLIME
+
+To setup slime with roswell, type like this
 
 ```
 ros -Q -e '(ql:quickload :quicklisp-slime-helper)' -q
 ```
 
 Add lines like below to init.el
+
 ```lisp
 (load (expand-file-name "~/.roswell/impls/ALL/ALL/quicklisp/slime-helper.el"))
 (setq inferior-lisp-program "ros -L sbcl -Q run")
 ```
+
 to load with `.sbclrc`
 
 ```lisp
@@ -81,6 +96,11 @@ to load with `.sbclrc`
 
 - [Rudolph-Miller/chef-roswell](https://github.com/Rudolph-Miller/chef-roswell)
 
+## Why we named it 'roswell'?
+From ‘[made with secret alien technology](http://www.lisperati.com/logo.html)’.
+
+I felt making it easier to use Lisp for people is a kind of making opportunity for humanbeings to mingle with alien technology. I recall ‘roswell incident’ by the concept. I'm not sure what you feel.
+
 ## See Also
 + [keens/cim](https://github.com/keens/cim) : similar project that is implemented in shellscript.I motivated to implement roswell by seeing this project.