Reword README

README

@@ -1,11 +1,11 @@
 lxd-openwrt
 ===========
 
-Scripts for building LXD images from OpenWrt rootfs tar balls. The OpenWrt SDK is used to build a patched procd package.
+Scripts for building LXD images from OpenWrt rootfs tarballs. The OpenWrt SDK is used to build a patched procd package.
 
 Requirements
 ------------
-Subversion is required in addition to the software needed to build the packages on the SDK.
+Subversion is required in addition to the software needed to build packages on the SDK.
 (Refer to https://openwrt.org/docs/guide-developer/obtain.firmware.sdk).
 
 Configuration