Fixed crash on saving a newly created archive-less map
Grid size can now be changed at any time
Add numpad enter as a default key for accept
Merge pull request #82 from Gaerzi/master

Sync with my fork.
Fixed some minor warnings/potential problems picked up by VS code analysis
Fixed problem with undo of architecture merge (gotta be more careful with argument names overriding class variable names >_>)
Merge branch 'master' of https://github.com/sirjuddington/SLADE.git
Merge branch 'master' of https://github.com/sirjuddington/SLADE