tests: improved Latte tests, removed codefix()
Latte: optimizePhp() moved to Latte\Helpers
Latte: optimizePhp() supports <?xml declarations
Latte: new Engine API
tests: Latte tests updated for new API
Latte: Compiler::$defaultContentType replaced with setContentType() (BC break)
Latte: added Parser::setContentType()
Latte: deprecated Nette\Templating\FilterException, replaced with Latte\CompileException (BC break)
Latte: uses its own caching mechanism (BC break)