Make Range::is_end explicit so that we can represent DWARF5 ranges wi…

[rocallahan]

…th start==end==0

Resolves #322

[rocallahan]

Note that this is a breaking API change because gimli users can construct Ranges explicitly and will need to add is_end: false.

However I don't see any way to avoid some breaking API change here.

[coveralls]

Coverage increased (+0.003%) to 84.804% when pulling 0d9f897 on rocallahan:range_is_end into ccbf294 on gimli-rs:master.

[philipc]

I don't see anywhere that you set is_end: true. I think we can simply delete that assert instead, since RawRngListEntry::parse never returns these entries for version 4 anymore (it used to). Same for the !is_base_address assert.

[rocallahan]

Range::parse sets it. But OK, deleting the assert is fine.

[philipc]

Range::parse sets it.

Ah yeah, my bad.

[philipc]

Thanks!