Adding support for parallel build (/m) and adding proper regex for error...

...s format in parrallel mode

When "/m" switch is provided, msbuild has significant build speedup, but errors looks like
```
    21>C:\Projects\Libra\Libra.PMS\Clients\Desktop\Libra.PMS.Desktop.DefaultTheme\Navigation\NavButtons.xaml(10,67): error MC3072: The property 'Foreground' does not exist in XML namespace 'http://schemas.microsoft.com/winfx/2006/xaml/presentation'. Line 10 Position 67. [
```
So we need take care about "21>" at the beginning of the line