zplugin: Large uplift of snippets: 1) no extendedglob dependency,
zplugin: Large uplift of snippets: 1) no extendedglob dependency,

2) more comfortable directory structure – directory with meaningful
   part of URL is shared among snippets,
3) support for Prezto, Zplugin will handle `pmodload' calls, i.e.
   dependencies,
4) support for Prezto plugin names (which are not "init.zsh"),
5) support for Prezto `functions' directory (it's added to fpath),
6) fixed snippet loading – it was blocked by improper set of
   conditional parameter,
7) better message on improper use of snippet (passing directory-URL
   instead of file-URL),
8) fixed location of .zplugin_url and .zplugin_mode files.

psprint/zplugin,psprint/zplugin,psprint/zplugin