Renamed Float validator to IsFloat
Renamed Float validator to IsFloat

PHP 7 marks "float" as a reserved keyword; this patch renames the
`Float` validator to `IsFloat` for forward compatibility. A later patch
will re-add the original class with a deprecation notice in the
constructor.

Maks3w/zend-validator,akrabat/zend-validator,weierophinney/zend-validator,zendframework/zend-validator,ezimuel/zend-validator,zf2timo/zend-validator,svycka/zend-validator