Gets rid of element ID requirement for multiple charts via data attribute

Also adds clickElement to multibarchart
Revert "Gets rid of element ID requirement for multiple charts via data attribute"

This reverts commit 5b00dda3ce87d199e13d567fc228f9d3ba19d095.
Removes unique ID requirement for multiple charts

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-If an element doesn't have an ID a custom data attribute with a random value is created
-New helper function checkElementID used in all of the chart directives
-Process events now responds to elementClicks for multibars
-New intro and outro.js files to wrap the entire library and unclutter global var space

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Part 2 of removing the unique ID element requirement.
Merge pull request #43 from dexdexdexdexdex/master

Removes unique ID requirement for multiple charts