Tweaks and polish

General improvements

• Project now has 100% line coverage 🎉
• Environment variables are now automatically captured in Pidget.AspNet #41
• Renamed RequestData to HttpData to stay more in line with the documentation.
• More documentation added

From #40:

• 4f74611: Simplified how FrameData is being extracted from the StackFrame.
• cdff287: fixed an embarrasing typo which meant that DeviceData.BatteryLevel would return null even if previously set.
• b9c17c5: removed the AbsolutePath property from StackFrame, it's never set, and rarely available (often not very helpful either), as it can often be found or extrapolated by classname / namespace, which always is provided.