Implement import from in symbol table

[Glyphack]

• Add import from statements to symbol table
• Update tests to pretty print import results

This is what we want to do for imports:

• import a: Adds an entry to the symbol table for the module a. The entry includes the module name and a flag indicating it is a module.
• from a import b: Adds an entry for b that points to the symbol b within the module a. The entry includes the symbol name, a flag indicating it is imported, and a reference to the module symbol a.
• from a import *: Adds an entry to symbol table with name *. This symbol table node will be used in another pass to actually copy the symbols from imported module in this table.

[ghodsizadeh]

Why did you do that?

[Glyphack]

Because it was unnecessary. Box should be used either for performance or for recursive structs and none are this case.