travis: code-checker checks whole repository
typo
travis: use php instead of php-cgi
improved phpDoc
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 '?'

Conflicts:
	tests/Utils/Strings.toAscii().phpt
Strings: added tests for few more UTF-8 edge cases
Strings::length uses mb_string if available
Strings::substring(): avoid calculating string length unless necessary
tests: fixed fixEncoding test
Json: workaroud for PHP fatal error caused by \u0000 at the beginning of key