Server side paging based on ng-grid.

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