less gender-specific reference in the opening paragraph

Rather than "fine fellows," which implies a boys' club, how about a slightly more inclusive alliteration? "Crafty coders" perhaps?
added fetch with blocks condition

blocks are lazy evaluated while the default value (provided as second argument) is eagerly evaluated
further refinement of opening paragraph
updated as per PR comments
Merge pull request #198 from dragosmiron/fetch-with-blocks

added fetch with blocks condition
style fix
Merge pull request #203 from dragosmiron/patch-1

style fix
Merge pull request #188 from drewda/patch-1

less gender-specific reference in the opening paragraph
Prefer Time.now over Time.new

The documentation says now is an alias for new. I believe Time.now more
clearly conveys that it uses the current time, whereas Time.new does not
convey the current time vs. an arbitrary, empty time object.

GitHub search indicates that Time.now is far more popular:

* Time.now has [376,997 code results](https://github.com/search?l=ruby&q=time.now&source=c&type=Code)
* Time.new has [18,858 code results](https://github.com/search?l=ruby&q=time.new&source=c&type=Code)

The ratio of now:new is approximately 20:1.
Merge pull request #206 from mark-rushakoff/time-new-now

Prefer Time.now over Time.new
Favor the use of predicate methods
Put fenced code block around shell command
Merge pull request #209 from lee-dohm/master

Put fenced code block around shell command
updated style guide with instructions for calling constructors
Merge pull request #210 from markijbema/add-constructor-exception

updated style guide with instructions for calling constructors
added examples of sprint hash syntax
Merge pull request #214 from markijbema/add-sprint-hash-syntax

added examples of sprint hash syntax
Extend identifier naming example
Show the difference in scoping between for and each (fixes #212)
Add a rule about Hash#has_key?