cppcheck issues

With SVN trunk, cppcheck finds these issues:

[Contrib/zip2exe/zlib/unzip.c:522]: (error) Possible null pointer dereference: s - otherwise it is redundant to check if s is null at line 526
[Contrib/zip2exe/zlib/unzip.c:525]: (error) Possible null pointer dereference: s - otherwise it is redundant to check if s is null at line 526
[Source/util.cpp:136]: (error) Memory leak: bitmap
[Source/icon.cpp:27]: (error) Resource leak: f
[Source/util.cpp:131]: (error) Resource leak: f
[Source/util.cpp:636]: (error) Resource leak: fdll
[Source/script.cpp:2813]: (error) Possible null pointer dereference: bufEHTStr - otherwise it is redundant to check if bufEHTStr is null at line 2812
[Source/script.cpp:1401]: (error) Resource leak: fp