Removed syntastic and replaced it with ale

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

sources_non_forked/ale/ale_linters/go/staticcheck.vim

@@ -0,0 +1,33 @@
+" Author: Ben Reedy <https://github.com/breed808>
+" Description: staticcheck for Go files
+
+call ale#Set('go_staticcheck_options', '')
+call ale#Set('go_staticcheck_lint_package', 0)
+
+function! ale_linters#go#staticcheck#GetCommand(buffer) abort
+    let l:filename = expand('#' . a:buffer . ':t')
+    let l:options = ale#Var(a:buffer, 'go_staticcheck_options')
+    let l:lint_package = ale#Var(a:buffer, 'go_staticcheck_lint_package')
+
+    " BufferCdString is used so that we can be sure the paths output from
+    " staticcheck can be calculated to absolute paths in the Handler
+    if l:lint_package
+        return ale#path#BufferCdString(a:buffer)
+        \   . 'staticcheck'
+        \   . (!empty(l:options) ? ' ' . l:options : '') . ' .'
+    endif
+
+    return ale#path#BufferCdString(a:buffer)
+    \   . 'staticcheck'
+    \   . (!empty(l:options) ? ' ' . l:options : '')
+    \   . ' ' . ale#Escape(l:filename)
+endfunction
+
+call ale#linter#Define('go', {
+\   'name': 'staticcheck',
+\   'executable': 'staticcheck',
+\   'command_callback': 'ale_linters#go#staticcheck#GetCommand',
+\   'callback': 'ale#handlers#go#Handler',
+\   'output_stream': 'both',
+\   'lint_file': 1,
+\})