Hardcoded EN Strings: Further hc strings eliminations + PL translation

resources added - Survey Screen:
"exception_draw_polygon"
"exception_draw_2_more_polygon_points"
"exception_draw_1_more_polygon_points"
"mission_is_too_lengthy"

Classes CircumscribedGrid,GridBuilder :
- property added (currContext)
- constructor changed:

checkIfValid (context param added)