ENYO-2949:prevent overwriting problem when creating a new file whiches difference is only capital and small letters of name

Enyo-DCO-1.1-Signed-off-by: Junil Kim <logyourself@gmail.com>
Merge pull request #504 from enyojs/ENYO-2949

ENYO-2949:prevent overwriting problem when creating a new file of which the difference is only capital and small letters of name