1.0.2 for php7

backport changes from php7 branch

Merge pull request iliaal#119 from johmue/prepack2

Requested pre-release PR (revised)

Re-tag

Version 1.0 release

* Added ExcelBook::IsDate1904/ExcelBook::ISetDate1904 methods to set/…

…retrieve base date format

* Allow compilation against LibXL 3.5.3