Update rust integration

vim/ftplugin/rust.vim

@@ -1,6 +1,10 @@
 let g:deoplete#sources#rust#racer_binary='/home/schneider/.cargo/bin/racer'
-let g:deoplete#sources#rust#rust_source_path='/opt/rust-src/src/'
+let rust_root = system('rustc --print sysroot')[:-2]
+let g:deoplete#sources#rust#rust_source_path=rust_root . '/lib/rustlib/src/rust/src'
 
 let g:ale_fixers = {}
 let g:ale_fixers['rust'] = ['rustfmt']
 let g:ale_fix_on_save=1
+
+nnoremap <F5> :w<cr>:!cargo run<cr>
+nnoremap <F6> :w<cr>:!cargo test<cr>