ExcelHandler updated version

About a year ago, I published the first release of the ExcelHandler library with the corresponding first NuGet package, it was the first experience with these powerful way of sharing code with the community. Since then, the time has passed and several things have happened, I received a pull request from Paulo Rezende that came with a good addition regarding to be able to get the number of sheets for a workbook, he also has some good ideas that I want to discuss with him and some of those are already in an experimental branch.

When looking for some kind of automatization at the moment of generating and publishing the NuGet Package, found an interesting Visual Studio Extension named NuGet.PackageNPublish.Extension that adds a new project template with the skeleton of a nuget package, it uses the text templating for recreate the .nuspec file each time the project is rebuilt and extracts as much as it can form the metadata in AssemblyInfo.cs file which is a good idea because the version and file names are prone to be out of synchronization when done manually.

Some of the improvement added to this library include: updated dependencies to newer versions, the NPOI and EPPlus libraries also evolved through the months, so there were some breaking changes that were changed in internal implementations for each dependency. Finally I added an automated test project, so it's not more necessary to run the console application sample. New elements in interfaces are:

• NumberOfSheets property in IExcelHandler interface, now it's possible to know the amount of sheets in a workbook.
• CreateSheet(string) method in IExcelHandler interface, now it's possible to add new sheets to a workbook.
• LoadExelFile(string) doesn't require the file exists in both implementations, so it can also be used to create new Excel files and not just for editing existing ones.

The current version of source code can be found at https://bitbucket.org/abelperezok/excelhandler/ and the NuGet Package at https://nuget.org/packages/ExcelHandler/. Hope this to be useful and any comment or issue will be welcome.