PrestaShop - Module dashboard

PrestaShop - Module dashboard

	A few new variables are necessary for a proper dashboard module:
		$this->push_filename: the directory where your push data should be stored.
		$this->allow_push: a boolean indicating whether your module should have data be pushed to it. or not.
		$this->push_time_limit: the numbers of seconds between two data pushes.


	PrestaShop 1.6 implements several new hooks dedicated to dashboard modules:
		dashboardData: how you want your data to be handled.
		dashboardZoneOne: enables you to display your content in the left column of the dashboard zone.
		dashboardZoneTwo: enables you to display your content in the central column of the dashboard zone.


	Params
		hookDashboardZoneOne
			@TODO
		hookDashboardZoneTwo
			date_from
			date_to
		hookDashboardData
			date_from
			date_to
			compare_from
			compare_to
			dashboard_use_push
			extra

	The data types
		There are 4 data types that your module can use:
		Value: a single value, which can have any data type (string, number, boolean, etc.)
		Trends: a specific type, available as an array two values:
			'way': either 'up' or 'down', depending on the trend
			'value': the difference between the past and current value.
		List Small: an array of values.
		Chart: an array of two values:
			'chart_type': the type of chart to be used (ie.: 'pie_chart_trends').
			'data': an array of arrays:
				key: the data key.
				y: the data value.

	Update push file:
		Tools::changeFileMTime($this->push_filename);