Add application category for OSX

When the Application folder is viewed by Arrange --> Application Category it will sort apps without LSApplicationCategoryType into "Other" at the bottom. This adds "Productivity" as the category.
Merge pull request #12 from duanemoody/master

Add application category for OSX
Fixed build issues (boost issues #7979 and #8971)
Merge pull request #13 from StaticDot/master

Fixed build issues (boost issues #7979 and #8971)
merge toc edit bug fix from KevinH.
Allow user defined list of entities to preserve.
Add the svg image tag as an svg inline element (not a block element) and add it as an empty element (TidyEmptyTags).
Fix GetRelativePathToRoot function for NCX and OPF resources.
Preliminary Python 2.7 Plugin Support for Sigil

Patches add preliminary support for using an already installed Python
2.7 interpreter to act as a plugin engine for Sigil
strike tag has been deprecated

replace strike tag with del tag to quite Flightcrew about deprecated
tags
fixes for minizip to play better with Cpp

add include ifdef guards and wrap include of windows.h in proper extern
"C" { }
plugin -  check for well-formed xhtml/xml

give user a chance to abort changes made by plugin if xhtml/xml to be
added/modified is not well formed
prevent plugin closing last tab and cleanups

prevent plugin closing last tab and cleanups
add python2_7 launcher folder
trying to properly commit python2_7 folder
trying once again to add new files
argh!
trying again to add python files after editing gitignore
fix for name clash in Windows with DeleteFile

changed Utility::DeleteFile to Utility::SDeleteFile
fix for missing endif in header guard