Enabled caching tiled rasters in catalog.

Also added a optional 'cache' flag to the ARG metadata json. This
will cache the specific layer, even if the DataStore does not have
it's 'cacheAll' flag set.
Merge remote-tracking branch 'upstream/master' into tile/caching
Made test tile rasters smaller.
Fixed failing test.
Taking conscript out of travis build.

The travis build keeps choking on trying to get conscript, so we've decided to just remove that section of the CI. This means the giter8 template will no longer be tested automatically.
Merge pull request #491 from lossyrob/tile/caching

Enabled caching tiled rasters in catalog.