Merge pull request progit#1088 from tirkarthi/master

Fix minor typos

Merge pull request progit#1081 from jingsam/patch-1

Add hash-object to validate ruby hash function

Merge pull request progit#1083 from rpjday/adv_merging

advanced-merging.asc: correct obvious typo, "lose" -> "preserve"

Merge pull request progit#1079 from rpjday/searching

searching.asc: mention that "git grep" can search the index as well

Merge pull request progit#1078 from rpjday/signing

signing.asc: Standardize on using "$" to represent command markup

Merge pull request progit#1077 from rpjday/revision_selection

revision-selection.asc: Clean wording; adjust commit numbers for June…

Merge pull request progit#1076 from rpjday/maintaining

maintaining.asc: standardize on "--" for em dashes, add italics

Merge pull request progit#1075 from rpjday/nutshell

nutshell.asc: minor tweaks for fonts/wording/emphasis

Merge pull request progit#1072 from rpjday/intro

Make some stylistic tweaks to Chapter 1, Introduction

Merge pull request progit#1073 from rpjday/basics

"Git Basics" chapter: tweak a couple things for aesthetics/clarity