fixed start up crash

using interface instead of attribute

pretty printing code

Removed redundant OperationList, using OperationAttribute instead

reduced the size of pbi.exe

added a feature switch Constants.USE_YAML_FOR_EMBEDDED_JSON

got yaml working;

working on changing the Layout json file to yaml to support nicer embedded json editing

updated binary

ignoring backups when exporting a pbix file

backing up pbix files before overwriting, not on import

auto backups on pbi import - retained for 5 days

inferring the filename where possible

created release.bat to build pbi.exe

updated readme