update readme to include blurb on decentralization

it occurred to me that someone discovering monero for the first time, through the code and actually reading the readme, would not have any indication of the design focuses of keeping monero decentralized, both in terms of the mining infrastructure and the low cost of node operation.  I know the topic is sort of a ... wishy washy thing, but I tried to craft some language that gets the point across in general terms.

README.md

@@ -67,6 +67,8 @@ Monero is a private, secure, untraceable, decentralised digital currency. You ar
 
 **Untraceability:** By taking advantage of ring signatures, a special property of a certain type of cryptography, Monero is able to ensure that transactions are not only untraceable, but have an optional measure of ambiguity that ensures that transactions cannot easily be tied back to an individual user or computer.
 
+**Decentralization:** The utility of monero depends on its decentralised peer-to-peer consensus network - anyone should be able to run the monero software, validate the integrity of the blockchain, and participate in all aspects of the monero network using consumer-grade commodity hardware. Decentralization of the monero network is maintained by software development that minimizes the costs of running the monero software and inhibits the proliferation of specialized, non-commodity hardware.  
+
 ## About this project
 
 This is the core implementation of Monero. It is open source and completely free to use without restrictions, except for those specified in the license agreement below. There are no restrictions on anyone creating an alternative implementation of Monero that uses the protocol and network in a compatible manner.