Extending wxFont API & OSX Core Text Implementation (#877)

* Switch to pure Core Text Implementation, Start extended Font API

* mac fixes

* First msw implementation

* Fixing paste error

* fixing typo

* Rearranging lines to former fallthrough order

* Blind fixes for covering new abstract methods

* Blind gtk implementations

* Fixing according to travis ..

* Removing method defined in base

* formatting adaptions

* Extending the schema definition for new weights

* fixing typo, using wxRound, other fixes according to comments

* changes according to suggestions

* fixing init order, before the init of m_info was overridden by Init()

* redo

* redo

* redo

* Cleanup

Removing obsolete code snippets, proper traces for font names

* Moving common code

Only the Get/SetNumericWeight calls should now be implemented in the native part, the ‚old‘ Get/SetWeight are common code and use the numeric counterparts.

* Updating docs

* commit wa missing changes.txt

* Doc fixes

* Full stops added

docs/changes.txt

@@ -155,7 +155,7 @@ INCOMPATIBLE CHANGES SINCE 3.1.0:
 
 - The enum value wxTASKBAR_JUMP_LIST_DESTIONATION, which was added in 3.1.0,
   contains a typo and has been renamed to wxTASKBAR_JUMP_LIST_DESTINATION.
-  
+
 - wxZipOutputStream will now automatically convert filenames to UTF-8, if the
   wxMBConv used when calling the constructor supports UTF-8 encoding.
 
@@ -489,6 +489,8 @@ All (GUI):
 - Allow suppressing warnings from wxImage::LoadFile().
 - Allow customizing wxRibbon highlight colours (wxBen).
 - Enable selecting opacity in generic wxColourPicker.
+- Extend the support for font weights to a bigger range.
+- Add support for fractional font sizes.
 
 wxGTK: