Update docstring for el-get-with-file-lock
Add "el-get-recipe-valid-p" predicate
Fix indentation
Fix first-line comment in generated recipe files
Add some dir- and file-related functions to internals
Better indentation for plists

This adds a custom "lisp-indent-function" for relevant keywords
Add el-get-warn-unless-in-subprocess

This provides an easy way to check whether code is executing in a
subprocess spawned by el-get. Functions that are indented for use only
in asynchronous subprocesses should call this function.
Fix comment in elpa fetcher file
Add el-get-package-manip

Currently it has functions for getting/setting package status (&
recipe) and fetching/removing packages.
Add basic file recipe for ack package

This recipe will be used for testing.
Update comments in el-get.el
Random test-related changes