Added validate!(item_id) to ensure proper item ID formatting

General cleanup of item.rb
Added spec to validate error condition when bad item ID is used

Refactored all rspec
Merge pull request #77 from eklein/validate_id

Validate ID before saving item
Update readme and changelog and bump version to 2.2.0
Fixes #79: "Released" date of version "v2.2.0"

Fixes #79: Corrected "Released" date of version "v2.2.0"

Existing "Released" date is showing as "## v2.2.0 / 2013-01-21" which is not correct. Corrected to "## v2.2.0 / 2014-01-21". Year should be 2014 not 2013!
Wrong year for recent update
Merge pull request #80 from techish1/master

Fixes #79: "Released" date of version "v2.2.0"
Merge pull request #82 from lamont/patch-1

Wrong year for recent update