Remove unnecessary history save

The intro saves and restored the current state via toJSON/fromJSON.
More reliable method for mutexed localStorage saves

Fixes #1883
Don't show combobox menu with only one item
Fix misspelling
Show all combobox entries when clicking the caret (fixes #1755)
Make the combobox caret a larger target
Add translated name tag only when language and value are both present

Fixes #1796
Fixes #1797
Fix changing localized language
Disable removing incomplete relation members (fixes #1768)
Fix adding localized value before name (#1797)
Add None tile layer

Fixes #1472
More opacity options
Add preventDefault for click events (fixes #1771)
Add additional check to prevent snapping to area fills (fixes #1887)
Omit non-OSM features from search results (fixes #1890)
Add delete button to all forms, closes #1492
Removed the remove option from radio preset
Update translation
Fixes blank hover state for Structure field, closes #1891
Fixed radio placeholder assignment