Create class to clean up pulling Fluo data from Key/Value pair

Fluo stores extra data in Key/Value pairs returned from Accumulo. This data is retrieved using masks. It would cleaner to hide this hide the masking from the user and create in data class that could be called KeyValue.

Current

``` java
Entry entry = iterator.next()
long colType = entry.getKey().getTimestamp() & ColumnUtil.PREFIX_MASK;
long ts = entry.getKey().getTimestamp() & ColumnUtil.TIMESTAMP_MASK;
```

Using KeyValue

``` java
KeyValue kv = iterator.next()
ColumnType colType = kv.getColumnType();
long ts = kv.getTimestamp();
```