Make it work for `express` about stc

[kdy1]

I updated the issue

[sunrabbit123]

Was it fixed because of #99?
If not, can you indicate what work remains?

@kdy1

[kdy1]

@sunrabbit123

stc_ts_file_analyzer:

• find_imported_var: Support namespace imports.

stc_ts_type_checker:

• Process all typings before processing user-specified files. This is required to handle modules created using declare module 'http' or declare namespace NodeJs.
• Handle declare module "http".