Merge pull request #2 from hatbot-team/surin-dev

Surin dev
Fix explanation key and prior_rating type decoding
Fix typo with return instead of raise
Add None check while applying modifiers
Fix typo and some PEP8
Add `with` statement support for ExplanationStorage.
Add single resource build
Merge pull request #3 from hatbot-team/closeable-storage

Make ExplanationStorage closeable
Fix Explanation's decode, repr and str
Move storages to storage, assets to assets, build_assets to tools
Split repo into package 'hb_res' part and preparation.

Something weird is still with asset deployment
Add some common modifiers

Their syntax is somewhat ugly, but I just can't figure out how to support informative repr in a better way.
Rewrite definitions with new modifiers. Have to disable checks for a while
add flags to re modifiers
Fix modifiers' repr format for kwargs
Fix lang_utils' imports
Fix Title/Text modifiers
Rewrite modifiers with fancy decorators
Merge branch 'modifiers' into definitions
Add introduction docstring