Zonal operations.

- Note raster-based zonal operations use .global, so the raster will converge.
- Moved combine and combineOp to DataSourceLike.
Merge remote-tracking branch 'upstream/master' into refactor/datasource
Merge pull request #621 from lossyrob/refactor/datasource

	Zonal operations for DataSource refactor
Switched catalog parsing to use Typesafe Config.

Fixes #55
Merge pull request #623 from lossyrob/catalog-typesafe-config

Switched catalog parsing to use Typesafe Config.
Don't skip over 0 values in Convolve, set as 0.

Fixes #467
Fix radius checking issue in IDWInteroplate.
Merge pull request #628 from lossyrob/idw-bug

Fix radius checking issue in IDWInteroplate.
Update gdaltest.sh to use gdal_translate.

The new gdal no longer includes gdal2xyz, so the gdaltest.sh script
is updated to use gdal_translate -of xyz instead.
Add test re: rasterizing polygons on cell centers.

Fixes #620.  This commit adds a test that confirms that the example
included in #620 is being rasterized correctly -- or at least that
the behavior matches gdal's.
Merge pull request #629 from joshmarcus/issue_620_rasterizer_test

Add test re: rasterizing polygons with vertices aligned with cell centers.
Created an overload .dispatch with no ActorRef argument.

Fixes #627
Changed dev application.conf port
Merge pull request #625 from lossyrob/convolve-bug

Don't skip over 0 values in Convolve, set as 0.
Merge pull request #631 from lossyrob/auto-router-distribute

Created an overload .dispatch with no ActorRef argument.
Added spark project
Merge pull request #637 from lossyrob/spark-project

Added spark project
Renamed name in Operation.

Fixes #507
Merge pull request #638 from lossyrob/operation-name-rename

Renamed name in Operation.
Initial commit of isNoData and isData macros.

Still need to figure out how to make those functions import nicely
with just `geotrellis._`. Aims to fix #624