Add additional Polygon feature constructors.
Add method to Extent to return feature.
Add documentation to ArgWriter.
Move Implicits to the directory corresponding to package name.
Add tests for tiled rasters to CroppedRasterTest.
Remove package.scala from geotrellis.op.

Everything that used to be in the geotrellis.op package object
has been moved to the geotrellis package object, and
geotrellis.Implicits was moved a directory up based on its
package name.
Merge pull request #200 from joshmarcus/wip_polygon_constructors

Miscellaneous clean up and minor features.
Add test to ensure tile origin is upper left.
Resolve issues with tiled rasters.

The tiles were being generated with the origin tile placed in the lower
right position (like TMS) but the specification is for the origin tile to
be placed in the upper left.

This commit also adds a new map/reduce style operation class with a
build in threshold for how many operations to run in parallel.
Merge pull request #203 from joshmarcus/topic/tile_issues

Fix tile layout issues and add parallel threshold.
Resolve bug in CroppedTiledRasterData apply().

The bounds check for y was incorrect in the apply method, causing CroppedTiledRasterData
to return NODATA when the apply (as opposed to the get(x,y)) was used.
Remove extra import.
Merge pull request #205 from joshmarcus/wip_fix_masked_ard

Resolve bug in CroppedTiledRasterData apply().
Add in Convolution Operation

Adds an operation that will convolve a given point spread fn
(kernel) with a raster. It also include a simple Gaussian
operation to create a raster with a Gaussian distribution

Also includes tests.

This is the first of a few commits that will hopefully replace
the old kernel density with a better tested implementation
Add a note to Setting up GeoTrellis about catalog.json location

In an attempt to be tidy I tried to store a catalog.json file
for a project in the same directroy as the rasters and metadata files
for that project. This caused a service failure because GeoTrellis
attempted to read the catalog.json as raster metadata.

This commit adds a note to the documentation explaining that the
catalog file must be kept out of the data directory.
Merge pull request #207 from ahinz/topic/convolution

Add in Convolution Operation
Merge pull request #208 from jwalgran/master

Add a note to "Setting up GeoTrellis" about catalog.json location 
Rearranged test hierarchy to match naming scheme.

This checkin resolves a conflict with the package geotrellis.op and the
new function geotrellis.op.
Refer to io._ ops with prefix.
Add new simple syntax for creating operations.

This checkin adds a new syntax for transforming a function into an
operation, with the op function(s), and tests.

If you define a function that returns a literal value, an operation to
be executed, or a StepResult (indicating success or failure) the function
can be turned into an operation by passing it to the op function.

For example,

1) A literal value, e.g.

   val plusOne = op { (i:Int) => i + 1 }

2) An operation to be executed:

   val localPlusOne ( (r:Raster, i:Int) => local.Add(r,i + 1) )

3) Or a StepResult (which indicates success or failure)
     val plusOne = op { (i:Int) => Result(i + 1) }