outputdir fix and per project settings if available

Hi,
This fixes bug #29 and resolves the issue of not having settings per project. I noticed there's already a branch addressing this issue but changes were reverted. Anyway here's a much simpler solution. Hope you merge it to master, for me at least it works.
So, how to use it. Inside a project, go to project, edit project and add
```json
"settings":
    {
        "less2css":
        {
            "autoCompile": true,
            "lessBaseDir": "./",
            "main_file": "myfile.less",
            "minify": true,
            "outputDir": "static/css",
            "outputFile": "",
            "showErrorWithWindow": false
        }
    }
```
In any case, if these settings are missing from the project settings the normal user settings are used.