tracyQ: fixed to work with SVG [Closes nette/tracy#87]

Regression of bug nette/nette#1365
UserPanel: is rendered when headers are not sent or session is active
RoutingPanel: improved dumping of objects [Closes nette/application#42]
MemcachedStorage: the key must not include control characters or whitespace [Closes nette/caching#13]

https://github.com/memcached/memcached/blob/master/doc/protocol.txt#L41
FileJournal: fixed 'Link is not in node' exception [Closes nette/caching#12]

That bug occur only in debug mode
netteForms: Nette.getValue returns value of radio/checkbox
netteForms.js: getValue returns bool for checkbox (fixes 8a69b763)
RequestFactory: optimized UTF-8 validation performance
Url::unescape() optimized for performance
ObjectMixin: nearly not measurable optimizations
Html: floats in attributes are printed in natural notation [Closes nette/forms#50]
Strings::substring(): unified behavior when both start and length are negative

behavior of iconv_substr is inconsistent with mb_substr (http://3v4l.org/JvOlj)
Strings::toAscii(): unsupported characters are removed instead of being replaced with '?'
Strings::length uses mb_string if available
Strings::substring(): avoid calculating string length unless necessary
Json: workaroud for PHP fatal error caused by \u0000 at the beginning of key
improved phpDoc