Fixed some broken offset calculations in the printProofScript method
Increased the visibility of the CacheSlot class
Added a load path provider CacheSlot to the load path configuration page

This slot will be used to track load path changes before they're written to
the project
Explicitly require the use of UTF-8 when communicating with coqtop

This commit makes Unicode characters work properly on Windows, and should
hopefully fix a related bug on Mac OS X