cppcheck: some cleanings

[libavogadro/src/textrenderer_p.cpp:215]: (error) Memory leak: rawbitmap
[libavogadro/src/textrenderer_p.cpp:249]: (error) Memory leak: glyphbitmap
[libavogadro/src/textrenderer_p.cpp:267]: (error) Memory leak: outlinebitmap
[libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:415] -> [libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:417]: (warning) Variable 'skip' is reassigned a value before the old one has been used. 'break;' missing?
[libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:417] -> [libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:419]: (warning) Variable 'skip' is reassigned a value before the old one has been used. 'break;' missing?
[libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:419] -> [libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:421]: (warning) Variable 'skip' is reassigned a value before the old one has been used. 'break;' missing?
[libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:421] -> [libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:423]: (warning) Variable 'skip' is reassigned a value before the old one has been used. 'break;' missing?
[libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:423] -> [libavogadro/src/extensions/surfaces/openqube/gaussianset.cpp:425]: (warning) Variable 'skip' is reassigned a value before the old one has been used. 'break;' missing?
[libavogadro/src/extensions/quantuminput/gamessinputdata.cpp:42]: (style) Array index 'test' is used before limits check.
[libavogadro/src/extensions/quantuminput/gamessinputdata.cpp:1654]: (style) Array index 'TitleStart' is used before limits check.