* Do not always show graph title.
Setting the default title too early cause the titles to always be shown.
AFAIK, they should only be shown when:
- title is set by the user or graph itself (not 100% sure)
- the title variable is set
* Use default for empty titles too
* Don't clean titles so aggressively
* Only show title if explicitly shown
* A little more consistent default titles
* use built-in escape
* Actually show user titles if set
Handle single quotes in title
* initialize title
* $title doesn't need to be nullable
add method getTitle() to always get some text
* Revert incorrect formatting change
* whitespace fix
* Return GraphImage to include more metadata
Allows things like including title.
Implements __toString for backwards compatability
getImageData to allow controlling the output through flags
* Style and Lint
