Remove outdated default args syntax
* implement Inspect for keyword in maps
* add basic tests for inspecting maps
* add basic support for inspecting structs

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>
Temporarily disable consolidation since we cant handle both records and structs at once
Implement Enum for maps and add map_size to Kernel
Implement access and slightly reorganize tests
implement updates on maps