normalize versions and update changelog

[chuckreynolds]

readme says Stable Tag: 1.4
https://plugins.svn.wordpress.org/batcache/tags/1.4/readme.txt

readme in github says Stable Tag: 1.2

file says Version 1.2 in 1.4 branch
https://plugins.svn.wordpress.org/batcache/tags/1.4/batcache.php

i haven't diff'd files with what's on wp repo but i'd hope this repo would be currrent

While you're at it fix the url too (rem extend/ slug) ;)

Plugin URI: http://wordpress.org/extend/plugins/batcache/

[lukecav]

The downloaded version from Repo, the file will show as being batcache.1.4.zip if you download the zip file, but as correctly stated in the batcache.php file it shows the version as being 1.2.