Enhancements, new features and bug fixes,

Fixed shear flow for zero N and M.
Fixed a runtime error for when the shear strength of a whole wall segment goes to zero during ULS analysis.
Incorporated version check so users can easily check if they got the latest release.
Incorporated validity check of geometry, including wall thickness, wall length and clockwise definiton of section.
Enhanced the visualisation of the results by adding different transparent shadings together with introducing matching colouring of the result checkbox labeling.