Addded spell check to .vimrc, whitespace removal

Can now trigger spell checking with <leader>s
Can now remove all trailing whitespace with <leader>w

Signed-off-by: Mattijs Korpershoek <mattijs.korpershoek@gmail.com>
Added amazing base16-solarized color theme
Signed-off-by: Mattijs Korpershoek <mattijs.korpershoek@gmail.com>