Interface changes

• Added LicenseKey property to all three Licenser classes as an alternative licensing method. 

• Added two AbstractFile.MoveTo overloads which accept an AbstractFile as the destination. 

• Corrected typo in FileSystemItem.DoCopyTo parameter.

Behavior changes that may affect your projects

• Now keep any SFX data found before the start of the zip file itself.

Other minor changes and bug fixes

• Improved documentation. 

• Avoid raising progression events twice for 100%. 

• Avoid raising ScanningFolder event for folders evaluated but not scanned for contents. 

• Corrected problem with QuickZip.GetZipContents when passing a single string filter.