-Changed all of the commonly used queries to keep around pre-prepared statements and bind
        their arguments instead of constructing a messy.  
        -Changed some code in pruneUnretainedIconsOnStartup regarding transactions

        * loader/icon/IconDatabase.cpp:
        (WebCore::IconDatabase::IconDatabase): Initializers
        (WebCore::IconDatabase::close): Wipe all the preprepared statements
        (WebCore::IconDatabase::pruneUnretainedIconsOnStartup): Better handling of transactions
        (WebCore::readySQLStatement): Make sure a preprepared statement is ready to go for a fooQuery()
        (WebCore::IconDatabase::pageURLTableIsEmptyQuery): Added a comment
        (WebCore::IconDatabase::imageDataForIconURLQuery): Use preprepared statement + binding
        (WebCore::IconDatabase::timeStampForIconURLQuery): ditto
        (WebCore::IconDatabase::iconURLForPageURLQuery): ditto
        (WebCore::IconDatabase::forgetPageURLQuery): ditto
        (WebCore::IconDatabase::setIconIDForPageURLQuery): ditto
        (WebCore::IconDatabase::getIconIDForIconURLQuery): ditto
        (WebCore::IconDatabase::addIconForIconURLQuery): ditto
        (WebCore::IconDatabase::hasIconForIconURLQuery): ditto
        * loader/icon/IconDatabase.h: Added fooQuery() and *m_fooStatements
        * loader/icon/SQLStatement.h:
        (WebCore::SQLStatement::database): Added



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@16056 268f45cc-cd09-0410-ab3c-d52691b4dbfc