add some more docs for the features that I've added so far..

README.md

@@ -1,9 +1,33 @@
 casimport
 =========
 
+This is a python module that is designed to load Python code from a
+cryptographic hash.  The idea is that instead of having to package
+up simple code as a Python package, you can import it directly via
+the hash.
+
+There is the concept of aliases to make the import statements easier
+to read.  This is currently limited to packages (on disk).  An example
+is the randpkg in the fixtures directory.  You can put a file named
+cas_aliases.txt along side your __init__.py file.  Each line of the
+file is:
+```
+<alias>	<url>
+```
+
+Where alias is a simple name, and url is a location to find the file
+at.  Currently, at least on hash url that follows the
+[hash-uri](https://github.com/hash-uri/hash-uri) format w/ a hash
+value of sha256.  The other supported url type is ipfs.  The format
+follows the [IPFS Addressing](https://github.com/ipfs/in-web-browsers/blob/master/ADDRESSING.md)
+document, and it is recommend that CIDv1 addresses are used, as the
+host portion of a URL is case insensitive, and CIDv0 (the current
+default) values are case sensitive.
+
 Usage
 -----
 
+Top level usage:
 ```
 import casimport
 from cas.v1_f_330884aa2febb5e19fb7194ec6a69ed11dd3d77122f1a5175ee93e73cf0161c3 import hello
@@ -11,7 +35,7 @@ from cas.v1_f_330884aa2febb5e19fb7194ec6a69ed11dd3d77122f1a5175ee93e73cf0161c3 i
 print(repr(hello('Alice')))
 ```
 
-Defintion of hash:
+Defintion of module names in cas package:
 v<num>_<type>_<arg>
 
 Currently v1 is defined, and has the following types: