Build atlas with the generic options recommended by the upstream
documentation for distributions. The expression now takes the parameter
'threads' which configures the number of threads atlas will use. The
default is to build serial atlas ('threads = "0"'). The expression also
takes the parameter 'cacheEdge' which is the L2 cache per core, in
bytes. This reduces build time because the cache size doesn't need to be
detected. It also reduces impurity, since different build nodes on Hydra
may have different hardware. It is set to 256k by default, which is
recommended for distributions by the upstream documentation.
(My OCD kicked in today...)
Remove repeated package names, capitalize first word, remove trailing
periods and move overlong descriptions to longDescription.
I also simplified some descriptions as well, when they were particularly
long or technical, often based on Arch Linux' package descriptions.
I've tried to stay away from generated expressions (and I think I
succeeded).
Some specifics worth mentioning:
* cron, has "Vixie Cron" in its description. The "Vixie" part is not
mentioned anywhere else. I kept it in a parenthesis at the end of the
description.
* ctags description started with "Exuberant Ctags ...", and the
"exuberant" part is not mentioned elsewhere. Kept it in a parenthesis
at the end of description.
* nix has the description "The Nix Deployment System". Since that
doesn't really say much what it is/does (especially after removing
the package name!), I changed that to "Powerful package manager that
makes package management reliable and reproducible" (borrowed from
nixos.org).
* Tons of "GNU Foo, Foo is a [the important bits]" descriptions
is changed to just [the important bits]. If the package name doesn't
contain GNU I don't think it's needed to say it in the description
either.
Update julia and some of its dependencies
Split PCRE because a lot of packages depend on it and I am not sure we
want to test them in a hurry (and Julia specifies exact version).
