Fixed installation of tomorrow-theme.

I tried installing tomorrow-theme but it didn't work very well for me. For example, both the post-init and the autoloads generation added incorrect paths to custom-theme-load-path. I've disabled the generation of autoloads (note, using `:autoloads nil` didn't work for me until I merged #1373 into my el-get) and fixed the path in post-init. With these changes I can now use `customize-theme` to select the various Tomorrow themes.