Fix always falling back to IL offsets instead of using line numbers

If `fNeedFileInfo` is not set to true when constructing a `StackTrace` (see http://msdn.microsoft.com/en-us/library/dsay49kt(v=vs.110).aspx), then the file names, line numbers, and column numbers will not be captured. As a result, SharpBrake always falls back to using IL offsets instead.

This is illustrated by the following code snippet:
```csharp
using System;
using System.Diagnostics;

namespace ConsoleApplication1
{
	class Program
	{
		static void Throw()
		{
			throw new Exception("TestError");
		}

		static void PrintStackTrace(StackTrace stackTrace)
		{
			foreach (var frame in stackTrace.GetFrames())
			{
				Console.Write(frame);
			}
		}

		static void Main(string[] args)
		{
			try
			{
				Throw();
			}
			catch (Exception e)
			{
				PrintStackTrace(new StackTrace(e));
				Console.WriteLine("--------------------------------");
				PrintStackTrace(new StackTrace(e, true));
			}
		}
	}
}
```

Output:
```
Throw at offset 78 in file:line:column <filename unknown>:0:0
Main at offset 53 in file:line:column <filename unknown>:0:0
--------------------------------
Throw at offset 78 in file:line:column c:\Users\Jeff\Desktop\SharpBrake\src\ConsoleApplication1\Program.cs:10:4
Main at offset 53 in file:line:column c:\Users\Jeff\Desktop\SharpBrake\src\ConsoleApplication1\Program.cs:25:5
```