Add code to handle ownCloud servers running on IDN

ownCloud instances can run on servers having an internationalized domain
name. This commit adds a conversion function between ASCII and Unicode.
The conversion function is used in the Authenticator and Preferences
activities.

See issue #469.
Merge branch 'idn_hosts' of https://github.com/ogasser/android into idn_hosts

Conflicts:
	src/com/owncloud/android/authentication/AuthenticatorActivity.java
Merge branch 'develop' into idn_hosts
Full-account synchronization should never fetch the contents of a folder
if its eTag did not change
Bump app version to 1.6.1
Bump workaround app version to 1.0.19
Merge pull request #675 from owncloud/hotfix_full_sync_ignoring_etag

HOTFIX - Full-account synchronization should never fetch the contents of a folder...
Merge branch 'master' into develop
[tx-robot] updated from transifex
[tx-robot] updated from transifex
[tx-robot] updated from transifex
[tx-robot] updated from transifex
Merge branch 'develop' into idn_hosts
Merge pull request #673 from owncloud/idn_hosts

Suuport for URLs to ownCloud servers running on IDN
[tx-robot] updated from transifex
Merge remote-tracking branch 'upstream/develop' into develop