Modified cmake GCC_VERSION from 4.2 to 4.0, our officially supported GCC version

Reviewed by Richard

Addition of Windows version for completenes. No changes.

EXP-755 FIX [PUBLIC] 'Search' and 'World Map' links in Sidebar are unclickable

fixed issues with UI scaling and text layout as well as incorrect text editor rect transforms


reviewed by Callum

Fixed setting the initialized flag for the decomposition stub case
(for OS builds) so that the viewer doesn't hang when initializing the stub.

Note that initialized will be set to true even when instance will return NULL.

Added more NULL checks for llconvexdecompositionstub, to avoid
crashing. Clients won't be able to upload meshes using the stub,
but should be able to run the client otherwise.