initialize .gitignore in Pkg.generate with *.jl.cov and *.jl.mem
ignore *.jl.cov and *.jl.mem
add code coverage via Coveralls.io to default package generation
add LGPLv2 and GPLv2 licenses to Pkg.generate
add CC0 universal to Pkg.generate()
warn if a package name is already in metadata
update documentation for new licenses and generation details