fix to be able to use columns parameter of searchGrid together with multipleSearch: false

fix undefined `colnm` and `cmi === -1` in case when `columns` parameter is specified.
Update grid.formedit.js

remove unneeded quoting characters.
Merge pull request #456 from OlegKi/master

fix usage of `columns` parameter of `searchGrid` in combination with `multipleSearch: false`