Mapping and AxisArrays integration

• Added mapping capabilities through PyCall and Basemap python module
• ClimGrid type is now supported for all functions (indices and mapping functions)

netCDF extraction

Added a function to extract netCDF files.

ClimateTools 0.0.3

Added new indices and better test coverage.

• Thresholds based indices
• Annual max and min values

ClimateTools 0.0.2

Added new climate indicators: "summernights", "icingdays" and "tropicalnights"