Changed sentence structure and grammar

Capitalized word after period
Added created in vs. in which

Change-Id: If3e91a0dc291304acb895f17b52e083aa0f868a0
Made changes to sentence structure.

Changed using to used to create
added transition word "the"
changed customize to customizes
Corrected run on sentence

Change-Id: Ib5ac773de5e11ca1f39aa93275f21376729e5d9e
centos-image-resize -> linux-rootfs-resize

The image guide links to an external project to build resizeable
virtual machine images. Its name changed from centos-image-resize
to linux-rootfs-resize.

Update the image guide to reflect this change.

Change-Id: I802530237aee91c110f9241497a0a2f0988e0c83
Merge "Changed sentence structure and grammar"
Merge "Made changes to sentence structure."
Merge "centos-image-resize -> linux-rootfs-resize"