Add basic qmllint support (#1419)

* Add basic qmllint support

* Use temp file, remove superfluous error code key, adjust author info

* Add qmllint handler parse test

ale_linters/qml/qmllint.vim

@@ -0,0 +1,29 @@
+" Author: pylipp (www.github.com/pylipp)
+" Description: qmllint for QML files
+
+" Find lines like
+" /home/foo_user42/code-base/qml/Screen.qml:11 : Expected token `}'
+function! ale_linters#qml#qmllint#Handle(buffer, lines) abort
+    let l:pattern = '\v^[/_-a-zA-z0-9\. ]+:(\d+) : (.*)$'
+    let l:output = []
+
+    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        let l:item = {
+        \   'lnum': l:match[1] + 0,
+        \   'col': 0,
+        \   'text': l:match[2],
+        \   'type': 'E',
+        \}
+        call add(l:output, l:item)
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('qml', {
+\   'name': 'qmllint',
+\   'output_stream': 'stderr',
+\   'executable': 'qmllint',
+\   'command': 'qmllint %t',
+\   'callback': 'ale_linters#qml#qmllint#Handle',
+\})