Merge pull request #1272 from Codezerker/master

Add a luac linter for Lua

test/command_callback/test_luac_command_callback.vader

@@ -0,0 +1,16 @@
+Before:
+  runtime ale_linters/lua/luac.vim
+
+After:
+  call ale#linter#Reset()
+
+Execute(The default command should be correct):
+  AssertEqual ale#Escape('luac') . ' -p -',
+  \ join(split(ale_linters#lua#luac#GetCommand(1)))
+
+Execute(The luac executable should be configurable):
+  let g:ale_lua_luac_executable = 'luac.sh'
+
+  AssertEqual 'luac.sh', ale_linters#lua#luac#GetExecutable(1)
+  AssertEqual ale#Escape('luac.sh') . ' -p -',
+  \ join(split(ale_linters#lua#luac#GetCommand(1)))