Removed vim-nerdtree-tabs to fix Name Collision

vim-nerdtree-tabs was being installed twice and since Vundle prevents users of having 2 plugins with the same name on the .vimrc file.

https://github.com/gmarik/Vundle.vim/issues/494
Merge pull request #2 from axierjhtjz/master

Removed vim-nerdtree-tabs to fix Name Collision