fix and rename nuspec file
allow registration of only a specific version of CSharp

Please see issue #13 where we had some discussions on this matter.
This commit brings some extension methods to help and an example
of how those would be used.
change nuspec to alpha2

new nuget packages will upload as 1.0.0-alpha2-buildnumber
directly from appveryor
dont nuget pack symbols, use nuspec not csproj

Symbols are unnecessary as we are not providing a library
If we pack the csproj it includes a lib folder as if we
were packing a library and also incluides our package deps
as deps in our package (but this could be disabled)
fix typo on readme
Dog fooding CodeCracker

Add CC nuget as dependency
Fix warnings
fix ForInArrayAnalyzer where it would break when array was not in scope

If array in the `for` declaration was declared outside the method scope
the symbol would not be found and an null reference exception would
be thrown. See associated test to an example of the now fixed case.
Merge pull request #57 from giggio/allowForSpecificVersionOfCSharp

Allow registration of only a specific version of CSharp
Merge pull request #62 from giggio/DogFoodingCodeCracker

Ok.
Merge pull request #63 from giggio/FixArrayInForEachAnalyzer

Fix ForInArrayAnalyzer where it would break when array was not in scope