settings: updated schema

active-proxy key now saves a string
added use-default key
build: updated dependencies version
window: added setting <-> action binding

win.use-default action binded to setting.
removed unused widget declarations
app: added setup routines

added settings::did-setup key
added routine to Utils module to create file and folders
added hook to Window object to setup the application
misc: fix formatting issues
row: added functionality to the widget

added Row::uid property
added Row::modififed signal
added initial saving details functionality
hooked save button status to host_entry contents
app: updated add action handler

migrated to new Row API
removed separator
removed demo code
window: update row_activated handler

migrated to use Row::uid
updated active-proxy settings
improved filtering code for rows not being Row instances
app: added saving of proxy data

Every row puts its data into a Variant and finally gets dumped
to a file. The same is opened and readed on startup.
Missing code for recreating rows from the loaded data.
window: handle VariantParseError exception
window: replaced error call for printerr
roadmap: updated