Captialize meta.description of all packages

In line with the Nixpkgs manual.

A mechanical change, done with this command:

  find pkgs -name "*.nix" | \
      while read f; do \
          sed -e 's/description\s*=\s*"\([a-z]\)/description = "\u\1/' -i "$f"; \
      done

I manually skipped some:

* Descriptions starting with an abbreviation, a user name or package name
* Frequently generated expressions (haskell-packages.nix)

pkgs/development/lisp-modules/lisp-packages.nix

@@ -345,7 +345,7 @@ let lispPackages = rec {
   command-line-arguments = buildLispPackage rec {
     baseName = "command-line-arguments";
     version = "git-20141113";
-    description = "small library to deal with command-line arguments";
+    description = "Small library to deal with command-line arguments";
     deps = [];
     # Source type: git
     src = pkgs.fetchgit {