Simplify snippets_engine and main
Autocomplete on Tab and only one suggest
New Editor GUI
Dialog to add snippet, new IO utils, constants
FIX: Convert dict to corrent snippet
Complete editor
Fix duplicating then modifying
FIX: Clean entries when last label removed
FIX: Save position when modifying snippet
Pretty print json
FIX: Callback in main when returning value is None
Checking in addition dialog
Checking in modifying
Space are allowed in params
Merge updated version into master