Search: RegEx not on par with DPRv1

[dangeol]

Ticking RegEx check box or not makes no difference.

Ensure the following cases work before closing this issue:

• āmi\b which should list hundreds of results -> this will be fixed by Search: broken functionality for strings containing diacritics #56
• For example when searching for arahan.* , it makes no difference whether Regex is checked or not. To be consistent with DPRv1, unticking RegEx should give no results for arahan.*