Multi-language support of search and error fix.

[1] Multi-language support of search.

'\w' doesn't match for the multi language.
( '\w' is [A-Za-z0-9_]. )

[2] The error by inputting double quotation as search term was fixed.

If search term  that include a double quotation mark is used, an error occurs.
Exsample search term:  
t "
" " "
etc.

So, I corrected.

Regards,
arbk