Change Worksheet function visibility from private to protected in ord…

…er to class extending. We have created small package on top of the Spout for support cell number format and per cell styles.

Prevent error when close() called while writer already closed (box#402)

Fix crash when using associative array with empty row (box#354)

Move ReaderCommonOptions class to Common folder (box#343)

Apply custom style to empty cells if needed (box#307)

Fixes box#295

If a row should be written with a custom style, the handling of empty cells should change.
Instead of being skipped entirely, empty cells will be applied the custom style, if this style has custom background color or borders.
If not, then the cell definition can still be skipped.

Shared strings table without uniqueCount and count should work (box#269)

Use file based strategy in this case

Merge pull request box#199 from box/check_valid_resource_on_close

Check file handle is valid before manipulating it

Merge pull request box#187 from skeleton/issue-183

Fix line breaks on CSV reader

Merge pull request box#173 from sfichera/master

Support for variable EOL for CSV

Merge pull request box#167 from box/fix_int_float_value_formatters

Fix CellValueFormatter for numeric values