Added an implementation that do not use mirrors
Annotate mustach_context with @MirrorsUsed

fixes #22
Made the used of mirrors configurable class wide
allow the mirros deactivation on the main library
Merge branch 'issue23'

fixes #23
Added some more documentation regarding the mirrors used stuff
Use the environmental variable USE_MIRRORS

in order to define if teh mirrors package should actually be
used
Updated the documentation
Merge branch 'issue23'