strip newlines from tree entry names

ported from github.com
Add pipeline option to native method. Disabled by default. Dont allow pipeline for grep
VERSION file and dynamic gem date
Cleanup
Merge branch 'tree-entry-newlines' of https://github.com/mojombo/grit into newlines
Version 2.6.2

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Adds "quick_diff" feature to Commit class.

Returns "unbaked" Diff instances with only the a_/b_path, new_file, and
deleted_file props set.