core -> extra for mac
Added overview of the debuginfo module at the beginning of debuginfo.rs.
Fixed compiler warnings about unnecessary string allocations in debuginfo.rs
Reordered debuginfo.rs and commented public fns
debuginfo.rs: Removed some static constants not used anymore.
debuginfo.rs: Explained why a function is called although one could think it should not be.
debuginfo.rs: Removed trailing whitespace.