LB-704: On chained blog providers some blogs has HTML formating on title and description

Mark blog title and description safe.
LB-705: On configure blog add http: in at the beginning of provider link

Allow urls starting with // and remove http placeholder.
LB-446: SMS source plugin
* filtering of posts by allowed sources of a given source type
LB-446: SMS source plugin
* adjusted: to avoid mismatches after merging from aap
Merge pull request #161 from petrjasek/lb-704-external-title-desc

LB-704: On chained blog providers some blogs has HTML formating on title...
Merge branch 'devel' into sms-filtering-devel

Conflicts:
	plugins/livedesk/livedesk/impl/blog.py
SMS filtering
* merge fix
Merge pull request #166 from msat-cont/sms-filtering-devel

LB-446: SMS source plugin
Merge pull request #162 from petrjasek/lb-705-provider-link

LB-705: On configure blog add http: in at the beginning of provider link