Undefined behavior in destructors

[pmarcelll]

I recently started to use Arch Linux after an old Ubuntu system and wanted to use the always up-to-date packages. I installed the cppcheck utility and tested it on the hawaii-shell codebase. I've found a similar bug in three destructors:
src/server/shell.cpp:192
src/server/effects/inoutsurfaceeffect.cpp:73
src/server/effects/minimizeeffect.cpp:97

After calling erase(), the iterator becomes invalid, so ++i is undefinde behavior.
The solution is decribed here: http://stackoverflow.com/questions/4260891/can-i-remove-elements-from-stdlist-when-im-iterating-on-it.

[pmarcelll]

There are also a couple of warnings, for example:
src/server/workspace.cpp:115 two returns in a function
members are not initialized in constructor
missing copy constructor (class contains a pointer to allocated memory)
...

[pmarcelll]

I forgot to close it, but it's okay now.

[pmarcelll]

I ran cppcheck again on the dev branch, cdb8751 added back the redundant return (55362ce).