Merge 'tag-cloud' into 'staging'

See merge request arsnova/topic-cloud!14

[Merge Request: !14]

do not show category drop down when no tags available, fix style, change...

Closes #34

See merge request arsnova/topic-cloud!13

do not show category drop down when no tags available, fix style, change button background when selected

This commit is partial and does not support full functionality.
The limitation of the tags within the cloud does not work yet.

[Ticket: #32]

[Ticket: #33]

We needed to use the EventService to bring the data from the
tag-cloud component into the header component. The event is
called every time we analyze new data in the tag cloud.

[Ticket: #16]

The angular-tag-cloud-module did not reset scaling when custom angles were set.

# Conflicts:
#	src/app/components/shared/tag-cloud/tag-cloud.component.scss
#	src/app/components/shared/tag-cloud/tag-cloud.component.ts

Merge Request for tag-cloud-configuration for staging

See merge request arsnova/topic-cloud!5

[Ticket: #15]

Merge branch 'tag-cloud-administration' into 'staging'

See merge request arsnova/topic-cloud!9

Added Option to Discard Filters and select questions from now on

See merge request arsnova/topic-cloud!7

# Conflicts:
#	src/app/components/shared/shared.module.ts

Keywords to be selected

Closes #3

See merge request arsnova/topic-cloud!8