GUI: new logo and gwt version

- Bumped GWT version to 2.6.1.
- Use new logo as backup if not set on server side.
- New favicon and Perun's LargeIcon
GUI: post instance name in RT reports

- If user submits error report, paste also name of Perun instance.
- Value is stored in /etc/perun/perun-web-gui.properties as
  perunInstanceName=[some_value]
  If not present, "UNKNOWN INSTANCE" is returned.
Merge pull request #355 from zlamalp/instance

GUI: post instance name in RT reports
Merge pull request #352 from zlamalp/logo_and_gwt

GUI: new logo and gwt version

- Bumped GWT version to 2.6.1.
- Use new logo as backup if not set on server side.
- New favicon and Perun's LargeIcon.
Add new methods for get data with Vos

- add method getDataWithVos (new structure with Vos before Resources)
- add method getRequiredAttributes for service and vos
- add these methods to RPC
- fix privilageException message in ServiceManagerEntry, method
  getDataWithGroups
Merge pull request #356 from stavamichal/getDataWithVoAttributes

Add new methods for get data with Vos
Added authz right for engine

Role.ENGINE can call ServicesManagerEntry.getAssignedServices(sess, facility)
Fix security issue with propagation to DNS alias

Facility manager can create destination to any free hostname (or IP
adress). The "free" means that name is not used on other facilty as a
destination or host's name. Exception from this is when the manager is
also facility manager on such facility.
Therefore any facility manger could create destination to any machine
(using IP address on other alias) and create resources with any services
(like sshkeys_root or k5login_root) and Perun will propagate there the
configuration.

Perun-slave now contains two variables DNS_ALIAS_WHITELIST and
FACILITY_WHITELIST which contains from which destinations or
which facilities the perun-slave accepts new configuration.
By default slave only accepts configuration from `hostname -f`.
Add log_debug function to perun slave script

If $DEBUG env. variable is set then this function logs to syslog.
Otherwise it does nothing.