Added libthreading.tex ; this is mostly the contents of threading_api.py,  with LaTeX markup added, and some small rewrites to improve the prose.
Added libthreading.tex ; this is mostly the contents of threading_api.py,
 with LaTeX markup added, and some small rewrites to improve the prose.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator