feat: importing files in Kin

[pacifiquem]

Fixes #169

Importing files in Kin

How

zana x kuva_muri "./path.kin"; # Looks-up `x` in provided path and bring it in current environment
zana * nka x kuva_muri "./path.kin"; # Binds every declaration in provided path and add them in [key]:[value] pair in x object
zana x, y, z  kuva_muri "./path.kin"; # Looks-up `x, y, z` in provided path and bring it in current environment

Rules

• Circular imports throws an error.

if file a imports file b, file b shouldn't import file a or import anything which depends on file a

• Namespace imports are added in a single object named by alias, not flat variables.

zana * nka x kuva_muri "./path.kin"; will bring everything from path and put them under x object

• Both relative and absolute paths are allowed