Server side paging based on ng-grid.

Thought I would see if there was any interest before unit testing.

Basic Usage:
```
self.gridOptions = {
	....
	pagingOptions: {
		pageSizes: [10, 25, 50, 100],
		pageSize: 25,
		currentPage: 1
	},
	columnDefs: [
	....

onRegisterApi: function(gridApi) {
	self.gridApi = gridApi;
	gridApi.paging.on.pagingChanged($scope, function () {
		self.getPage();
	});
	}

self.getPage = function () {
	$http.post("/users", {
		pageNumber: self.gridOptions.pagingOptions.currentPage,
		pageSize: self.gridOptions.pagingOptions.pageSize
	}).success(function (data) {
		self.gridApi.grid.options.totalServerItems = data.totalItems;
		self.items = data.items;
	});
};
```