Split searchText & selectedOption.text

[moreta]

Semantic UI's Search Selection using <div class="text"></div> for selected contents.

vue-search-select don't.
After first select then click input once more vue-search-select do not show options.
Because searchText alread placed with full option text.

This should be fix.

[moreta]

• Prop name change from reset-trigger-value to trigger-value
• We can propagate default(or change) item or reset item from parent to child by trigger-value
• Now delete key reset item

[moreta]

closes #5