Support other windowing features

[shivamka1]

pub trait TimeOps<'graph>:
    InternalTimeOps<'graph, InternalWindowedView = Self::WindowedViewType>
{
    type WindowedViewType: TimeOps<'graph> + 'graph;

    /// Create a view including all events between `start` (inclusive) and `end` (exclusive)
    fn window<T1: IntoTime, T2: IntoTime>(&self, start: T1, end: T2) -> Self::WindowedViewType;

    /// Create a view that only includes events at `time`
    fn at<T: IntoTime>(&self, time: T) -> Self::WindowedViewType;

    /// Create a view that only includes events at the latest time
    fn latest(&self) -> Self::WindowedViewType;

    /// Create a view including all events that have not been explicitly deleted at `time`
    ///
    /// This is equivalent to `before(time + 1)` for `EventGraph`s and `at(time)` for `PersitentGraph`s
    fn snapshot_at<T: IntoTime>(&self, time: T) -> Self::WindowedViewType;

    /// Create a view including all events that have not been explicitly deleted at the latest time
    ///
    /// This is equivalent to a no-op for `EventGraph`s and `latest()` for `PersitentGraph`s
    fn snapshot_latest(&self) -> Self::WindowedViewType;

    /// Create a view that only includes events after `start` (exclusive)
    fn after<T: IntoTime>(&self, start: T) -> Self::WindowedViewType;

    /// Create a view that only includes events before `end` (exclusive)
    fn before<T: IntoTime>(&self, end: T) -> Self::WindowedViewType;
}