Merge pull request #2885 from wmertens/pgadmin-1.18.1

pgadmin: bump to 1.18.1
Merge pull request #2855 from cstrahan/xpwn-fix-darwin

Fix xpwn on Darwin and other case-insensitive file systems
systemd service: fix issues with escaping when unit name contains '-'

systemd escaping rules translate this into a string containing '\'
which is treated by some code paths as quoted, and by others as unquoted
causing the affected units to fail.
libtasn1: 3.4 -> 3.6. Fixes some security CVEs.

Closes #2844, #2857
mesa: maintenance update 10.1.4 -> .5
dbus: security-only update, CVE-2014-3477 (DOS)
mesa: fix libGL searching for libudev

Close #2784, #2731.

I don't have a clue if using our libudev is always correct on non-nixos,
or if using /run/current-system/sw/lib/libudev would be better...
Create a PIL symlink when installing PIL so the recommended way of importing PIL.something works
Update MITMProxy
Update netlib
Update haskell-hspec to version 1.10.0
Merge pull request #2891 from sol/master

Update haskell-hspec to version 1.10.0
haskell-spawn: new package, v0.3
haskell-io-memoize: new package, v1.0.0.0
haskell-hspec2: new package, v0.3.0
Merge pull request #2893 from soenkehahn/master

New Haskell packages
Fix configuring httpd with custom user/group.
lilypond: cosmetic changes
all-packages.nix: cosmetic changes
haskell-libmpd: test suite build is broken by recent hspec update