initial implementation of raw writing of keywords in an xml template
refactored all into an own module and added support for CDATA in ElementTree
added note about CDATA in ElementTree
added tests for writing xml metadata
replaced teplate with one generated at http://inspire-geoportal.ec.europa.eu/editor/
added read keywords from iso file. not handling errors yet
added tests for writing xml metadata
added gui capabilities for setting defaults for iso metadata. 
I used the already present DEFAULTS method so that we have a central 
place in safe with all the defaults.
XML Template can now use the values from safe.defaults.get_defaults
added initial read write suport for non file based layers
allow generating xml without writing to file
clean up
PEP8
merged develop
Merged develop
imports cleanup
more pylint
fixed some issues
Merge branch 'develop' of github.com:AIFDR/inasafe into metadata
moved xml template to an xml file