Add on offline Exception.
Merge branch 'offline' of github.com:toomore/grs into class-except
Raise class.
Add error.py
Rename.
Update version.
Add error docs page.
Add `ConnectionError` into realtime.
Merge branches 'realtime' and 'class-except' of github.com:toomore/grs into v0.5.3rc

Conflicts:
	grs/realtime.py
Update docs.
Add error link into docs index.
Merge branch 'v0.5.3rc' of github.com:toomore/grs
Add alias into moving_average.
Add alias into moving_average_value.
Add alias into moving_average_bias_ratio.
Add alias into check_moving_average_bias_ratio.
TIny changed for docs.
Version update.
Update unittest.
Merge branch 'func-alias' of github.com:toomore/grs into v0.5.4rc