Add glossary terms for apple-specific C++'isms

[springmeyer]

Apple systems support dynamic libraries organized as Frameworks. Because this way of organizing C/C++ code is not cross platform we generally don't recommend or use Frameworks at Mapbox. To clarify that apple systems support both dynamic and static libraries in the same way as other unix systems (and this is our preferred best practice) we should add Frameworks to the glossary to describe how they differ.

[springmeyer]

another thing to add, specific to apple, would be an explicit definition of .tbd vs .dylib vs .a extensions for libraries in the glossary. The tbd showed up with xcode >=7 and stand for text-based stub libraries (https://stackoverflow.com/a/32115656). It is a yaml file that points to a dylib. A dylib is a dynamic library and is the same thing as an .so on linux. An .a is a static library and has the same file extension on linux and os x.