GEOMESA-551 removing extraneous flush from modify feature writer
GEOMESA-576 Common parameter casing and tools fixes

* All command line parameter use lower case, dash separated instead of camel casing
* Default to true for table sharing
* Boolean parameters have arity of 1 (require true/false instead of using a flag)
GEOMESA-574 Accept keyword list in WPS Import
GEOMESA-126 Improve GeoServer WMS GetCapabilities handling for time enabled layers

For time-enabled layers, GeoServer calculates the time extent by looking at all the features in a FeatureStore.
For large datasets, this is incredibly slow.  This pr helps rectify this issue by

* Calculating and updating a time interval while writing features to GeoMesa.
* AccumuloFeatureCollections retrieve stored time extent data in response to Min/MaxVisitors.
  If no such metadata is present, the interval returned is 1970 until now.
* Updating the Caching functionality to return a new CachingAccumuloFeatureCollection.
  Such CachingAFCs provide access to the AFC class and store the results of 'features' in a private lazy val.

NB: In order for this to work properly, there are two GeoServer related caveats:
1.  The SimpleFeatureType's name must match the layer name in GeoServer.
    If not, then GeoServer will wrap the AFC in a retyping collection.
2.  Given the current state of CRS handling, the layer must use SRS Handling 'Keep Native'.
    If not, GeoServer will wrap the AFC in a collection to force the declared CRS.

Either of these wrappings mess prevent GeoMesa from intercepting the visitors as intended and produce full table scans.
Merge branch 'accumulo1.5.x/1.x' of github.com:locationtech/geomesa into f_wcs_3