give Stack a virtual, public destructor, and add explicit breaks in a sw...

[teeler]

Explicit breaks during parsing, some random whitespace cleanups, and a virtual public destructor for Stack.

[teeler]

Oh i did break it..I thought this was already failing, looking.

[sparkprime]

It looks like this is still failing, on gcc because of parser.cpp:621:18: error: expected identifier before ‘[’ token

and on clang because of

parser.cpp:621:19: error: clang::fallthrough attribute is only allowed on empty
statements
[[clang::fallthrough]]
^
parser.cpp:621:39: note: did you forget ';'?
[[clang::fallthrough]]

[teeler]

Closing this for now until I can find a better way.

[sparkprime]

This is all now in trunk.