added driver install utility (dpinst 32- and 64-bit) and Arduino icon needed for Windows installer
changed the pin where to connect the button from 2 to 4 to be compliant with the comment in the header and the tutorial.
Fixes #1396
Merge branch 'master' of github.com:arduino/Arduino into LUFA_bootloader
updated driver description string to "Arduino USB Driver".  includes new .cat