Removed syntastic and replaced it with ale

Read more here:
https://github.com/w0rp/ale

sources_non_forked/ale/doc/ale-proto.txt

@@ -0,0 +1,33 @@
+===============================================================================
+ALE Proto Integration                                         *ale-proto-options*
+
+
+===============================================================================
+Integration Information
+
+Linting of `.proto` files requires that the `protoc` binary is installed in the
+system path and that the `protoc-gen-lint` plugin for the `protoc` binary is also
+installed.
+
+To enable `.proto` file linting, update |g:ale_linters| as appropriate:
+>
+  " Enable linter for .proto files
+  let g:ale_linters = {'proto': ['protoc-gen-lint']}
+<
+===============================================================================
+protoc-gen-lint                                      *ale-proto-protoc-gen-lint*
+
+  The linter is a plugin for the `protoc` binary. As long as the binary resides
+  in the system path, `protoc` will find it.
+
+g:ale_proto_protoc_gen_lint_options       *g:ale_proto_protoc_gen_lint_options*
+
+  Type: |String|
+  Default: `''`
+
+  This variable can be changed to modify flags given to protoc. Note that the
+  directory of the linted file is always passed as an include path with '-I'
+  before any user-supplied options.
+
+===============================================================================
+  vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl: