More Explorer commands and new InnoSetup support

arc1 updated:

• new, unicode-aware version of All2Arc utility
• added Add../Extract.../Modify.../Join.../Convert... commands to Explorer context menu
• added Convert command to FreeArc menu
• unarc.dll for extracting FreeArc archives in other programs
• example of Inno Setup installation script that extracts files from FreeArc archives using unarc.dll