nixos/graphite-service: fix startup issue

The preStart snippets (graphite, carbon) try to create directories under
/var/db/. That currently fails because the code is run as user
"graphite". Fix by setting "PermissionsStartOnly = true" so that the
preStart stuff is run as 'root'.

Further:
 * graphite-web-0.9.12/bin/build-index.sh needs perl, so add it to PATH.
 * Now that preStart runs as root, we must wait with "chown graphite"
   until we're done creating files/directories.
 * Drop needless check for root (uid 0) before running chown.
nixos/grahite-service: mkdir -m => mkdir && chmod

mkdir -m will only set the permissions if it *creates* the directory.
Existing directories, with possibly wrong permissions, will not be
updated.

Use explicit chmod so permissions will always be correct.
Merge 'master' into x-updates
mesa: major update 10.0.4 -> 10.1.1
xorg: minor updates of three packages
xorg-server: major update 1.14.5 -> 1.15.1
xorg: revert fontsproto update, as it breaks libXfont

This partially reverts commit 30ac332563318be4e445dc3335e803326df84d3c.
https://groups.google.com/forum/#!msg/xorg-devel/SvgqiQnSN7c/f0wjRhauqvUJ

It's sad that the currently *released* versions don't even compile together,
and no dev reacts for four days so far...
xorg-server: go back to 1.14.6 due to intel problems

Again, stable releases not compiling together :-/
Fix icu4c expression for latest gcc (fixes #2341)
Add expression for sage
Fixed pkgconfig support for poppler-qt4
Added TeXmaker package : an advanced editor for latex
Adding myself to lib/maintainers.nix
herbstluftwm: update to 0.6.2
jdk7: update patchversion 51 -> 55.
Bump mpv to 0.3.8
Add subtitle option for ffmpeg.
Fix whitespace
libmx: Add package
pythonPackages.chameleon: 2.11 -> 2.15