* Also update Bled to latest, as well as build scripts
* Note: Considering that Visual Studio 2015 is both freely and legally
available for anyone who wants to use it to compile Rufus, starting
with this commit, I will NOT be supporting any other version of Visual
Studio but 2015.
* part of issue #111
* add getopt dependency for MS compilers
* enable the provision of an ISO as parameter
* also fixes shadowed sevenzip_path in vhd.c