readimf 0.1.0

• Initial CRAN release.
• Access International Monetary Fund data through the new IMF ‘SDMX’ 3.0 API at https://data.imf.org, returned as a tidy imf_tbl with provenance.
• imf_weo() downloads World Economic Outlook series, including historical forecast vintages.
• imf_data() fetches any data flow by key. imf_dataflows(), imf_search(), imf_codelist(), imf_countries() and imf_dimensions() browse the catalogue and metadata.
• imf_ifs() routes retired International Financial Statistics codes to their new thematic data flows, and imf_ifs_map() shows the crosswalk.
• Named database wrappers with sensible defaults: imf_cpi(), imf_dots() (bilateral goods trade), imf_cofer() (reserve currency composition), imf_commodity() (primary commodity prices) and imf_gfs() (government finance). Balance of payments and financial soundness indicators are defined in the API but not yet populated, and will follow.