Update README.md

Merge pull request #4 from factset/fix-lgtm-warnings

Fix all instances of LGTM warning: No matching copy assignment operator

Fix all instance of LGTM warning: Constant return type on member

Merge pull request #3 from factset/fix1

Fix linker error on Ubuntu

Merge pull request #2 from factset/fix1

Remove unused function 'copyMember' in rpacket_entry_0103.cpp

Removed line in README stating that attributes are not supported

Added REXPList

Initial Commit