Lot of small cleanup changes

arc1.arc updated:

• GUI: after operation was completed, Cancel becomes the default key in progress dialog so you can close it by pressing just Enter/Space
• fixed bug in dict (addressing memory beyond end of buffer) and a few UI problems
• included latest InnoSetup scripts & dll
• Added license info to About and console help
• facompress.dll: now loaded only from directory where FreeArc executable resides since loading something from PATH may lead to FreeArc versions incompatibility
• LZMA: decompressor now writes data in 8mb chunks (instead of dictsize) that means smoother progress indicator
• error messages: now reports "read error" or "write error" instead of "i/o error"