Resolve "`VALUE` command does not print variable names"

• no direct evaluation in the VALUE command, also with the = delimiter (closes #480 (closed)).
• add spacing to VALUE output

In class Object:

• write std namespace explicitly
• small include cleanup
• fix typos

In class Value:

• small include cleanup

Note: the output after this fix is still different from the manual output. The manual will be changed accordingly once this MR is accepted.