Update sm64extend README to include 0.2.1 release changes

Author: queueRAM

release/sm64extend.README.txt

@@ -1,4 +1,4 @@
-## sm64extend 0.2: Super Mario 64 ROM Extender
+## sm64extend: Super Mario 64 ROM Extender
  - accepts Z64 (BE) or V64 (byte-swapped) ROMs as input
  - works with both US and Japanese ROMs (other tools may not)
  - decompresses all MIO0 blocks from ROM to extended area
@@ -7,18 +7,20 @@
  - configurable MIO0 block alignment (default 1 byte)
  - changes all 0x18 level commands to 0x17
  - creates MIO0 headers for all 0x1A level commands
+ - optionally dump compressed and uncompressed MIO0 data to files
  - optionally fills old MIO0 blocks with 0x01
  - updates assembly reference to MIO0 blocks
  - recalculates ROM header checksums
 
 ### Usage
 ```
-sm64extend [-s SIZE] [-p PADDING] [-a ALIGNMENT] [-f] [-v] FILE [OUT_FILE]
+sm64extend [-s SIZE] [-p PADDING] [-a ALIGNMENT] [-d] [-f] [-v] FILE [OUT_FILE]
 ```
 Options:
  -s SIZE      Size of the extended ROM in MB (default: 64).
  -p PADDING   Padding to insert between MIO0 blocks in KB (default = 32).
  -a ALIGNMENT Byte boundary to align MIO0 blocks (default = 1).
+ -d           dump MIO0 blocks to files in 'mio0files' directory
  -f           Fill old MIO0 blocks with 0x01.
  -v           Verbose output.
 
@@ -47,6 +49,9 @@ Pad 64 KB between blocks, align blocks to 16-byte boundaries, fill old MIO0 bloc
 sm64extend -p 64 -a 16 -f sm64.z64 sm64_output.ext.z64
 ```
 ### Changelog:
+v0.2.1: add dump option and ROM validity checks
+ - add dump (-d) command line option
+ - add more ROM validity checks on input file
 v0.2: more options, error checking, and allow extending SM64 (J)
  - add fill (-f) command line option
  - add more error checking up front and while extending