Add conversion methods to go from RasterMetadata to RasterDefinition

Add TmsTilingConvert which has methods to convert RasterMetadata to
RasterDefinition. This allows for three use cases:
1. geotrellis-spark can use any geotrellis methods that use RasterDefinition
2. geotrellis-spark can potentially pass RasterDefinition from op to op
3. geotrellis-spark can avail of the rich set of methods in RasterDefinition,
in particular methods in RasterExtent, and those in TileLayout and ResolutionLayout

Also in TmsTilingConvert are methods to convert tx/ty to gtTileIdX and gtTileIdY,
the latter being 0 based and starts at upper left
Add TestFiles and AllOnes to make it simple for tests to access commonly
used test rasters in geotrellis-spark
add RDDMatchers
modifications to use AllOnes
refactor LocalBinaryOpMethods out of Add
add AllTwos and AllHundreds to test files
add more flavors of shouldBe to RDDMatchers
explicitly set spark.master.port to 0 to trigger akka random port binding
minor change: organize imports
Disable parallelExecution for geotrellis-spark so suites can run serially
add -,*,/ to RasterRDD