update vim and zsh default config

vim : do not convert tab into spaces ..
zsh : vi alias + editor, screen alias

vimrc

@@ -7,10 +7,9 @@ let g:airline_powerline_fonts = 1
 filetype plugin indent on
 " show existing tab with 4 spaces width
 set tabstop=4
+set softtabstop=0 noexpandtab
 " when indenting with '>', use 4 spaces width
 set shiftwidth=4
-" On pressing tab, insert 4 spaces
-set expandtab
 " Enable highlighted search
 set hlsearch
 " Disable VIM matching parenthesis highlighting

zshrc

@@ -106,3 +106,10 @@ fi
 # no beep for console
 #setterm -blength 0
 #TODO if term console
+
+# force vim, usefull on FreeBSD that do not use update-alternatives stuff
+alias vi="vim"
+export EDITOR="vim"
+
+# force screen unicode to render powerfont correctly
+alias screen="screen -U"