Get height of every item using outerHeight().
Add and Remove methods to append / remove new elements into columns.
Generate a unique ID for those items that doesn't have an ID.
Added option to allow grab height from image attributes.
Fix code style.
Updated documentation.
Fix code style.
* Incorrect columnd width calculation.
Merge pull request #2 from clinisbut/feat-add-items

Added two methods to add and remove items.