Null pointer fix

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28105 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
changes and bugfixes (previewObjects and subToolBar)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28106 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Make sure CurrentFile variable is not static

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28107 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Adding --macSandbox option to use FileDialog instead of JFileChooser on a sandboxed Mac (backport to 4.4 needed, some other places should be rewritten in a second step)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28108 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Formatting

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@28109 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e