Modify release-notes for changes related to free tranactions

Add comment about free transactions no longer being the default
Inform about the relay policy change

doc/release-notes.md

@@ -79,7 +79,8 @@ This release automatically estimates how high a transaction fee (or how
 high a priority) transactions require to be confirmed quickly. The default
 settings will create transactions that confirm quickly; see the new
 'txconfirmtarget' setting to control the tradeoff between fees and
-confirmation times.
+confirmation times. Fees are added by default unless the 'sendfreetransactions' 
+setting is enabled.
 
 Prior releases used hard-coded fees (and priorities), and would
 sometimes create transactions that took a very long time to confirm.
@@ -88,10 +89,12 @@ Statistics used to estimate fees and priorities are saved in the
 data directory in the `fee_estimates.dat` file just before
 program shutdown, and are read in at startup.
 
-New command line options for fee estimation:
+New command line options for transaction fee changes:
 - `-txconfirmtarget=n` : create transactions that have enough fees (or priority)
 so they are likely to begin confirmation within n blocks (default: 1). This setting
 is over-ridden by the -paytxfee option.
+- `-sendfreetransactions` : Send transactions as zero-fee transactions if possible 
+(default: 0)
 
 New RPC commands for fee estimation:
 - `estimatefee nblocks` : Returns approximate fee-per-1,000-bytes needed for
@@ -273,7 +276,7 @@ server round-trip to execute.
 Other utilities "bitcoin-key" and "bitcoin-script" have been proposed, making
 key and script operations easily accessible via command line.
 
-Mining enhancements
+Mining and relay policy enhancements
 -------------------
 
 The `prioritisetransaction` RPC method has been added to enable miners to
@@ -293,6 +296,11 @@ if this is 1.
 - `-datacarriersize=n` : Maximum size, in bytes, we consider acceptable for
 "data carrier" outputs.
 
+The relay policy has changed to more properly implement the desired behavior of not 
+relaying free (or very low fee) transactions unless they have a priority above the 
+AllowFreeThreshold(), in which case they are relayed subject to the rate limiter.
+
+
 0.10.0 Change log
 =================