Make Readme much clearer and explain edits.

Also added some examples, but those should be mostly self-explanatory.

plugins/atom/README.md

 ## atom
 
-Plugin for Atom, a cross platform text and code editor, available for Linux, Mac OS X, and Windows.
+This plugin makes "at" a useful function for invoking the Atom Editor.
+
+Originally by Github user [aforty](https://github.com/aforty) for OSX, modified to alias 'at' to 'atom' for Linux, since atom already works on the terminal for Linux, and calling 'at' in a non-OSX environment should still work.
 
 ### Requirements
 
@@ -10,8 +12,12 @@ Plugin for Atom, a cross platform text and code editor, available for Linux, Mac
 
  * If `at` command is called without an argument, launch Atom
 
- * If `at` is passed a directory, `cd` to it and open it in Atom
+ * If `at` is passed a directory, open it in Atom
 
  * If `at` is passed a file, open it in Atom
 
- * if `att` command is called, it is equivalent to `at .`, opening the current folder in Atom
+### Examples
+
+ * Open the current dir in atom: `at .`
+ * Open another dir in atom: `at path/to/folder`
+ * Open a file: `at filename.extension`