cpp11 0.3.0

New functions and features

• New x.empty() method to check if a vector is empty (@sbearrows, #182)
• New x.named() method to check if a vector is named (@sbearrows, #186)
• New na() free function to return the NA sentinels for R objects (@sbearrows, #179)

Major fixes

• Memory no longer inadvertently leaks when move constructing vectors (#173)

minor improvements and fixes

• Incorrectly formatted cpp11 decorators now output a more informative error message (@sbearrows, #127)
• Generated registration code now uses C collation to avoid spurious changes from tools::package_native_routine_registration_skeleton() (@sbearrows, #171)
• Makevars files which include filenames now handle spaces in paths properly (@klmr, #160)