IAMconsortium/pyam: Release v0.3.0

Release v0.3.0 Highlights Streamlined generation of quantitative metadata indicators from timeseries data using set_meta_from_data() Better support for accessing public and private IIASA scenario explorer databases via the REST API More extensive documentation of the pyam data model and the IAMC format Compatible with recent pandas v0.25 Individual Updates #277 Restructure and extend the docs pages, switch to RTD-supported theme #275 Completely removes all features related to region plotting, notably region_plot() and read_shapefile() #270 Include variables with zeros in stack_plot (see #266) #269 Ensure append doesn't accidentally swap indexes #268 Update aggregate_region so it can find variables below sub-cateogories too #267 Make clear error message if variable-region pair is missing when check_aggregate_region is called #261 Add a check that keep in filter() is a boolean #254 Hotfix for aggregating missing regions and filtering empty dataframes #243 Update pyam.iiasa.Connection to support all public and private database connections. DEPRECATED: the argument 'iamc15' has been deprecated in favor of names as queryable directly from the REST API. #241 Add set_meta_from_data feature #236 Add swap_time_for_year method and confirm datetime column is compatible with pyam features #273 Fix several issues accessing IXMP API (passing correct credentials, improve reliability for optional fields in result payload