Attempt to fix setup script when numpy isn't present

* pip appears to be brokes; numpy can't be automatically installed as a dependency
* added instructions to README

README.rst

@@ -1,4 +1,4 @@
-ATRCopy
+atrcopy
 =======
 
 Utilities to list files on and extract files from Atari 8-bit emulator disk
@@ -7,7 +7,13 @@ images.  Eventually, I hope to add support for these images to pyfilesystem.
 Prerequisites
 -------------
 
-Starting with ATRcopy 2.0, numpy is required.
+Starting with atrcopy 2.0, numpy is required.
+
+The standard python install tool, pip, does not seem to be able to handle the
+automatic installation of numpy, so to install atrcopy, use::
+
+    pip install numpy
+    pip install atrcopy
 
 
 References

atrcopy.py

@@ -5,7 +5,10 @@ __version__ = "2.1.0"
 
 import types
 
-import numpy as np
+try:
+    import numpy as np
+except ImportError:
+    raise RuntimeError("atrcopy %s requires numpy" % __version__)
 
 
 class AtrError(RuntimeError):

setup.py

@@ -5,7 +5,12 @@ try:
 except ImportError:
     from distutils.core import setup
 
-import atrcopy
+try:
+    import atrcopy
+    version = atrcopy.__version__
+except RuntimeError, e:
+    # If numpy isn't present, pull the version number from the error string
+    version = str(e).split()[1]
 
 classifiers = [
     "Programming Language :: Python :: 2",
@@ -19,7 +24,7 @@ with open("README.rst", "r") as fp:
     long_description = fp.read()
 
 setup(name="atrcopy",
-      version=atrcopy.__version__,
+      version=version,
       author="Rob McMullen",
       author_email="feedback@playermissile.com>",
       url="https://github.com/robmcmullen/atrcopy",