export to celldesigner returns proper cell designer file

Additional unit tests



See merge request !4

Refactoring

issues #9, #10, #12

See merge request !3

Bug fixes

Issues solved:
#50, #31, #41, #46,  #38, #43, #48

See merge request !2

submaps are opening from link (when accessing it from coment tab in
admin panel), however centering is still not handled properly

issue #46 solved

there are two type of overlay colors:
* user scope (every user account have custom color schema)
* system scope used when user colors are not defined