add current density integrals in electric current module
ExtFunction introduced to generator
interface for external functions created
ext functions progress
progress
new ExtFunction implementation, synced with Hermes
rewrite of volume integrals - first step (simetimes segfaut, speed improvement needed)
surface integral - can be compiled, doesn't work
volume and surface integral progress
Merge remote-tracking branch 'kus/master'

Conflicts:
	agros2d-generator/generator_module.cpp
	agros2d-generator/generator_module.h
	agros2d-library/hermes2d/module.cpp
	agros2d-library/hermes2d/plugin_interface.h
	hermes/hermes2d/src/function/postprocessing.cpp
	resources/templates/generator/coupling_interface_h.tpl
	resources/templates/generator/interface_cpp.tpl
	resources/templates/generator/interface_h.tpl
	resources/templates/generator/weakform_cpp.tpl
synced with hermes
fixes