Add new icons to Assembly work bench

Including new body icons for the treeview and
PartDesign create new body command.
Move all Assembly constrains icons into their
own sub directory of the icons directory
add "STEP, IGES or BREP" to the tool tip
of Assembly add existing Component command
extend debug facilities with state writing and add externalisation to make it compile with a decent amout of memory
Merge branch 'ickby_assembly_with_new_icons_pull_request_1' of https://bitbucket.org/jmaustpc/my-clone-freecad-from-sf-git-master into assembly
Fix bug in PartDesign conversion that choked on unconsumed sketches
PartDesign::Transformed: Transformed shapes that touch are now rejected as overlapping in the interest of boolean operation stability
Reference highlighting for fillets and chamfers
Reference highlighting for fillets and chamfers (2)
Fixed crash after rejecting a MultiTransform dialog
Part Design: support for overlapping and coincident patterns

    Fixed crash after rejecting a MultiTransform dialog
    remove overlap check
    adding getSolid to cut operation
    add extrema method to part::checkinterference
    move refineshape call out of loops
    divideTools functions
Revert "PartDesign::Transformed: Transformed shapes that touch are now rejected as overlapping in the interest of boolean operation stability"

This reverts commit 22e90571fd9701b9e97c54749e80128b16bf6570.
Fixed usage of std::abs() in polar pattern
Merge branch 'refs/heads/tanderson-merge-assembly-pd-pattern' into dev-assembly
Update icon references in Task Assembly Constraint

to include the new sub-directory "constraints" in the path
for the Assembly constraints icons
update Assembly Workbench icon in InitGui.py
update Assembly constraint icons to cylinder theme
update remaining Assembly constraint icons to new theme

update remaining Assembly constraint icons
to new cylinder theme

Also increase the emphasis on the constriants
by thickening them, in the
Assembly_constraints_tree icon
multiple debug updates
Merge branch 'jriegel/dev-assembly' of git://git.code.sf.net/p/free-cad/code into assembly
add jims icons and add new files