Commented Task: Create a better first impression for developers [15447]

See full discussion here: https://opendbiff.codeplex.com/discussions/579065

Converting this project to Visual Studio 2013 and improving first-build & first-edit experience:

1. Add .gitignore
1. Upgrade solution and projects to VS2013.
1. Remove the setup project.
1. Replace the Ascend GradientPanel control with standard Panel.
1. Replace Scintilla code with DLL references.

Comments: Step 2: Upgrade solution and projects to VS2013. Pending pull request: https://opendbiff.codeplex.com/SourceControl/network/forks/drjustinhale/opendbdiff/contribution/7969