Ticket #3337: better handle old files (algebra view size fix)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26969 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
minor changes: selectAll() and overwrite existing files

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26970 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
removed scroller from AV and set AV directly to ScrollPanel, changed CSS accordingly

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26971 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
don't allow empty strings as filename

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26972 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
moved the headers to the header-package

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@26973 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e