Make Query Validation Explicit to User

[greenrhyno]

closes #37

Disables the Execute Query button based on the whether the currently built query is valid or not. Adds messages to each validation condition so that the user is notified (via a tooltip on the Execute Query button) of the exact reason why a query can not be executed.

Changes in this PR include:

• adding of a new AnchorButtonTooltip that allows for the tracking of hover behaviors even when the button is disabled
• refactor query validation to refer to an array of conditions with (localizable) error messages
• add a verbose version of validating the query that returns the first error message encountered
• adds CSS class for buttons with tooltips that need to be full width

[davelandry]

I'd like to wait for @frabarz to come back on the 31st to approve/merge/release this PR, just because some of these inner-workings go a bit over my head. From a conceptual standpoint I love this new feature, so as long as it doesn't interfere/break any other behavior let's go for it 👍🏻