Merge web.list() logic into get()

[dmitrizagidulin]

• Refactor web.get() to include the functionality of list(). That is, if the result of a get() is a container, return an instance of SolidContainer like list() does, and otherwise return the usual SolidResponse instance.
• Add an isContainer() convenience method to SolidResponse.
• Also, fix the type parsing logic (currently only parses one type, out of several)

[dmitrizagidulin]

Implemented. Closing.