Added a README file.

modified:   GSharpTools.sln
new file:   README.md
Fixed broken mailto link.

modified:   README.md
Added the GSharpTools.sln.GhostDoc.xml file.

This file is used by GhostDoc to maintain a solution-wide dictionary for
the spell check function.
Updated .gitignore to ignore [Cc]ode[_][Dd]rop/

The [_] basically says that the folder name may or may not contain an
underscore in that position.
Catch and handle System.IO.IOException CalculateMd5

Detect duplicates was throwing an unhandled exception and crashing when
I ran it against my SkyDrive folder. It was trying to calculate the MD5
hash for the .lock file, which is constantly in use by the skydrive
system tray app. This resulted in System.IO.IOException being thrown. I
handled it by first catching that exception and, if in DEBUG mode, write
a message to the console then return an empty string. Then, when that
hash was actually being used, I check to see if it's empty and if it is
I just return; out of the method instead of trying to process the empty
string.

I also applied quite a few ReSharper refactorings that made the code
much easier to read.

modified:   DetectDuplicates/CachedHashes.cs
modified:   DetectDuplicates/DetectDuplicates.cs
modified:   DetectDuplicates/DetectDuplicates.csproj
new file:   DetectDuplicates/Properties/Annotations.cs
new file:   GSharpTools.sln.DotSettings
new file:   GSharpTools.sln.GhostDoc.user.dic
Removed the gnp project

On the original solution file that was installed with the gtools
software package, there is a project named "gnp" that doesn't exist in
the solution folder.

modified:   GSharpTools.sln
Merge branch 'dev' of https://github.com/k4gdw/GSharpTools into dev