Add PCLZIP alternative to ZipArchive

Resolves #106
Merge and modify 'pclzip' of https://github.com/bskrtich/PHPWord to make it work with the latest develop branch
Merge and modify 'pclzip' of https://github.com/bskrtich/PHPWord to make it work with the latest develop branch
Merge branch '#140-bskrtich-pclzip' of github.com:ivanlanin/PHPWord into #140-bskrtich-pclzip
Refactoring & remove underscore prefix from method and property names
Namespace adjustments on writer classes
Namespace alias
Merge remote-tracking branch 'upstream/develop' into refactor-writer
Namespace updates
Refactor writer classes
Merge branch 'develop' of github.com:ivanlanin/PHPWord into develop
Merge branch 'develop' into #140-bskrtich-pclzip
Update changelog and documentation for PCLZip
Merge pull request #185 from ivanlanin/#140-bskrtich-pclzip

Add PCLZIP alternative to ZipArchive (merge and close #140)