[documentation] README.txt for Drupal core

[Angela Byron]

Hi, folks!

There's currently an issue in the Drupal core issue queue that could  
use some of your fine eyeballs: http://drupal.org/node/607028

The idea is to try and communicate some useful background/ 
philosophical information about Drupal and its approach to extending  
it, as well as resources that would be helpful to people new to using  
Drupal. The idea being to prevent the all-too-common situation now of  
people doing "worst practices" such as hacking core because they don't  
know any better.

Would appreciate your thoughts and reviews!

-Angie