I found it very frustrating working in Maya's default UV Editor window, so I decided to add many the wonderful scripts that I've found on this site and incorporate them into the UV Editor window. Thanks to Creative Crash users for all your free scripts. Especially...
// Brian Keffer one putting up one of his older scripts on Creative Crash (http://www.bk3d.com/)
// Stefan David for his sdv_xformUV scripts (http://www.stefandavid.com/posts/category/scripts/)
Place JC_uvMARS into your scripts folder. I have mine here \Documents\maya\2013-x64\prefs\scripts\
Place all icons into your icons folder.
I've included the icon 'JC_uvMARS.bmp' for you to add to your shelf.
Using the command 'JC_uvMARS()' will open a modified UV Texture Editor Window
with added functionality.
The 'Snap Align UV Shells' button will only allow you to select two UVs.
The first is from the UV shell you want to move and the second, the UV shell you wish to snap to.
Let me know of any bugs and I'll try to fix them or modify the script as you see fit for your needs.