Merge branch 'release-candidate' into develop ...

# Conflicts:
#	ClosedXML/Excel/XLWorkbook_Load.cs
#	ClosedXML_Tests/Resource/Other/StyleReferenceFiles/TransparentBackgroundFill/TransparentBackgroundFill.xlsx

Fix saving alignment

Fix loading transparent fill

Do not quote worksheet name with whitespace when saving pivot table worksheet source

Set IXLCell.Style.IncludeQuotePrefix to true if user sets IXLCell.Value to something that starts with single quote (in line with Excel)

Implement OpenXML's CellFormat.QuotePrefix

Reuse custom file properties part instead of creating new one

Implement the full range of Item subclasses for pivot tables ( https://msdn.microsoft.com/en-us/library/documentformat.openxml.spreadsheet.shareditems.aspx )

Clear all cell contents (formats too) in pivot table range upon loading.

Clear pivot table rendered range upon loading to avoid conflict on rendered cells when opening the file.

Allow pivot tables to have no theme

Correctly unprotect worksheet without password

Ignore pivot table data field base items that are out of range.

Update XLCell.MergedRange to use GetIntersectedRanges

Bug fix - unsupported CellValues.String Data type ...

Changes at workbooks loading and unit test with file example to test changes.

Pivot table: DateTime type with empty value (Issue #859 fix) (#860) ...

issue #859 : Pivot table: DateTime type with empty value

Update reference files (fills with patternType="none" removed)

Failing test added

Support table sources for pivot tables

Simplify XLCell.cs()

Load file's cached value into XLCell.CachedValue - need to some refactoring of the internal parsing in XLCell

Remove 2 files with vulnerabilities. They're not supposed to be loaded

Add and test LO files

Ranges handling redesign (proof-of-concept) (#766) ...

* Immutable range addresses implementation start

* Immutable range addresses implementation continue

* Range addresses made immutable

* Helper methods for range addresses introduced

* XLRangeRepository introduced

* Range factory introduced

* XLRow and XLColumn constructor calls replaced with factory methods.

* Range shifting with no callback actions implemented

* Ranges shifting improved

* Shifting of worksheet data called explicitly. Shifting of CF ranges fixed

* MergedRanges copying removed as it's performed with rows copying. Minor changes in reference file

* Test fixed (arguments reordered)

* Sharing implemented for tables

* Addresses comparison fixed. Formula shifting fixed

* Setters for FixedRow and FixedColumn removed

* Clean-up

* Flaky test fixed.

* Merge conflicts solved

* Make most of the classes non-disposable

* Clean up

* Merged ranges shifting fixed

* Remove redundant variables, clean up usings.

* Restore usings needed for Release configuration. Remove unused constructor (has been replaced with a method in XLWorksheet).

Change XLTable.Theme default value to TableStyleMedium2 to align with Excel

Сonsolidation of conditional formats and data validation rules (#761) ...

* Failing test added

* Multiple ranges for conditional format

* Clearing ranges of CF fixed.

* XLConditionalFormat.Range implemented via Ranges.

* Tests for CF copying added

* XLRangeConsolidationEngine implemented

* Conditional formats consolidation re-implemented.

* Data validaton rules consolidation implemented

* Tests fixed

* CF formula adjustment implemented

* Fix clearing formats not covered by cleared range

* Reference files updated (uncertain about changes). Adjusting CF formulas fixed

* Fix multi-range conditional formats loading. Fix CF consolidation to prevent reordering of rules.

* Fix formula shifting for multi-ranged conditional formats.

* Merge conflicts solved

* Range property made non-obsolete and returning First rather than Single

Move reference file to new Other\ folder

Fix pivot tables with totally blank field.

Merge branch 'develop' into StylesRebased ...

# Conflicts:
#	ClosedXML/Excel/Ranges/XLRanges.cs
#          ClosedXML/ClosedXML_Tests/Resource/Other/Charts/PreserveCharts/outputfile.xlsx

Don't delete DrawingsPart if there are charts