core: move requests session init & headers from login to init
core: login is private (__login__)
core: add __request__ method to manager "X-HTTP-Method-Override"
core: add item data parser function
core: update credits on every request (only if it is avaible included in response)
core: fix __request__
setup: copy metadata & parse requirements.txt
v0.0.3
Merge branch 'master' into stable