Add Gentoo instructions

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Vim: Add Syntastic

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Vim: Add neco-ghc

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Vim: Add vim2hs

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Vim: Add Haskell indent

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Vim: Add Haskellmode

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>
Vim: Add vim-hsimport

Signed-off-by: Alexander Berntsen <alexander@plaimi.net>