Readme.rst: Minor edits
dev/env.rst: Markup
dev/env.rst: Minor edits
index.rst: Minor source tweak

Reads easier when viewing the source
intro/duction.rst: Minor edits (formatting)
styleguide.rst: Github ▶︎ GitHub
docs/**: Specify language for code-blocks (syntax highlighting!  mmm…)
Readme.rst: put `pip` and `virtualenv` on separate bullets
dev/env.rst: Remove (body text) comma
dev/env.rst: Un-markup “site-packages”
notes/styleguide.rst: Add comma after “e.g.”

To any style-obsessed writers or editors reading this commit:

The comma (or lack of one) after “e.g.” or “i.e.” has always bugged me.  I finally looked it up!  Here’s what I found:

http://english.stackexchange.com/questions/16172/should-i-always-use-a-comma-after-e-g-or-i-e
writing/tests.rst: Unbold “``mock``”
Readme.rst: Capitalize “Pip” and “Virtualenv”
Merge pull request #393 from Zearin/code-blocks

Code blocks