+ do not allow negative numbers in fillet and chamfer panel
Arch: moved ifc-related functions to importIFC
Merge branch 'master' of ssh://git.code.sf.net/p/free-cad/code
+ add QuantitySpinBox
Transferred import-export related preference pages to a separate group
Arch: Starting Panel tool
Arch: Further work on panel
Arch: small fix in panel
Arch: Updated preferences page for panels
Arch: added panel to  cmakelist