Fixes for XCI parsing in Python 3.6

See merge request !23

Rework XCI file parsing

See merge request !22

- Support JSON format XCI files (#119)
- Support XCIX files (#120)

Added support for Microsemi Libero SoC

See merge request !6

libero.exe (in Windows world) refuses to load a TCL script when it is called in the way ../libero.exe SCRIPT: project.tcl; The problem is the whitespace there, so ../libero.exe SCRIPT:project.tcl works fine.

Fix #100