Corrected FPU exceptions disabling

Minor change so dependencies can use this library for exception re-ba…

…sing without inducing circular references

Removed dependence of extended exceptions on PurePascal symbol, funct…

…ion making registers snapshot made standalone and public, corrected several critical and many non-critical bugs

Corrected conversion of variants to strings

Reworked stack frames, minor other internal corrections

Reworked stack frames, minor other internal corrections

Added threads enumeration, completed the implementation

Added simple stack trace, allowed compilation for Linux OS only in FPC

Finalized implementation