pull module blacklist from Ubuntu and use it by default

People often have serious problems due to bogus modules like *fb.
lightdm: Update to 1.8.6
lightdm-gtk-greeter: Update to 1.6.1
silver-searcher: updated to 0.19.1
bangarang: fix build with gcc 4.7
vidalia: fix build with gcc-4.7
youtubeDL: update from 2014.01.23.4 to 2014.01.30.2
Update/fix merkaartor to 0.18.1
Use gcc-4.6.0 for avr-gcc-libc
dhcpcd: Update to 6.2.1

Dhcpcd now has integration with udev, so it should no longer be a
problem if udev renames an interface while dhcpcd is running.
Adding missing unistd.h includes
Update libcangjie 1.1
lttng-tools: use absolute path to modprobe

Instead of relying on it being available in $PATH.
hub: Update from 1.10.6 -> 1.11.1
Add pycangjie

[Bjørn Forsman <bjorn.forsman@gmail.com>: expression cleanup]
siege: Update to 3.0.6
siege: expression cleanup
nixos/nscd: add option to change nscd config

[Bjørn Forsman <bjorn.forsman@gmail.com>:
 - use types.lines instead of types.string. The former joins strings
   with "\n" and the latter with "" (and is deprecated).
]
Merge #1618: use ubuntu module blacklists by default
Merge #1645 and #1646: lightdm and -gtk-greeter update