Merge pull request #308 from patrickarlt/master

Docs for beta 6
added support for image service rendering rule

added test to spec for getter/setter functions
implemented getter/setter functions
updated _buildExportParams() to pass renderingRule if option is set
updated api reference page to include new option and getter/setter functions
added example page applying a hillshade to a DEM.

resolves #295
Add Rendering Rules page to examples TOC
Merge pull request #309 from tomwayson/issue-295

added support for applying a rendering rule to an image layer when exporting an image
added support for setting mosaic rule on export image

added test to ImageMapLayerSpec.js
implemented getter/setter functions and updated `_buildExportParams` in ImageMapLayer.js
updated api reference page
added example page using lock rasters to show only one raster in a mosaic
Merge pull request #310 from tomwayson/issue-298

added support for setting mosaic rule on export image
added support for image service nodata parameter

added tests to ImageMapLayerSpec.js
added getter/setter methods to ImageMapLayer.js
includes optional parameter to set noDataInterpretation when setting noData
updated api reference page w/ new option/methods

resolves #311
Merge pull request #313 from tomwayson/issue-311

added support for image service noData and noDataInterpretation parameters
Merge pull request #323 from patrickarlt/master

fix #210
added ImageServiceIdentifyTask

added spec to test default use case
added tests for ImageMapLayer.identify() factory method
added to karma files
renamed identify tasks to IdentifyFeatures and IdentifyImage
refactored common methods of identify tasks into Idenityfy.js
image identify requires geom sent as JSON, not x,y&sr=4326
added identify image example
added tests/props for mosaicRule, renderingRule, pixelSize
added api ref page for L.esri.Tasks.IdentifyImage
Correct case of "BaseMapLayer" to BasemapLayer"
Correct typos in description
Change param name `key` to `url`
Change param name `key` to `url`