Merge pull request #86 from fruppel/master

UTF-8 encoding for excel files
Fix #88: Enhanced EditableColumn to serialize grid keys for object or array
PSR 4 alias change
PSR 4 alias change
Fix #92:  Bug fix for generating multiple rows in header/footer
Upgrade to release v2.1.0
Minor code comments formatting
Fix #106, Close #107. Date range filter and refactor of gridview class code.
Fix #108: Enhance export jquery plugin to safely relocate grid export form.
Fix #107 Refactor of gridview class code.
Undo the fix for #108
Fix #111: Fix export button dropdown menu display for IE
Fix #109: Correct module initialization
Upgrade to release v2.2.0
Upgrade to release v2.2.0
Upgrade to release v2.2.0
Upgrade to release v2.2.0
Upgrade to release v2.2.0
Upgrade to release v2.2.0
Upgrade to release v2.2.0