Previous 'font' styling broken up into it's constituent parts: 'fontFamily', 'fontSize', 'fontStyle', 'fontVariant' and 'fontWeight'

Updated the style.fill documentation to reflect gradient options

Fixes @AMorporkian's TextStyle PR ...

As he himself worked out, there were a couple of style settings that weren't being set in TextStyle that were trying to be used in Text, thus causing issues.

Revert "Revert "A few JSDoc corrections relating to Text and TextStyle""

Revert "A few JSDoc corrections relating to Text and TextStyle"

Couple of JSDoc corrections

Revert "Switched TextStyle to version based instead of an EventEmitter. Changed" ...

This reverts commit 130bf46.

Switched TextStyle to version based instead of an EventEmitter. Changed ...

Text.updateText() to have a respectDirty parameter, to remove redundant
`if (this.dirty)` checks.

Added a getColor function.

Simplified TextStyle.reset()

Corrected JSDoc types for constructor and simplified constructor logic.

Changed style changed event to a constant. Remove event listener on Text ...

when attaching a new TextStyle to Text. Added a TextStyle.reset()
method.

Modified setters to prevent event from being emitted if the value is ...

unchanged.

Added TextStyle object, a reusable style setter for PIXI.Text.