strange string behaviour

[bgalek]

When trying to invoke o "stratsWith" method from String.class using opel expression, we found out that 'test'.startsWith('\t') or 'newtest.startsWith('\n') evaluates to true - which seems wrong.

    @Unroll
    def 'should return true!'() {
        given:
        def engine = new OpelEngineBuilder().build()

        expect:
        engine.eval(input).get() == expResult

        where:
        input                      || expResult
        /'atest'.startsWith('\a')/ || false
        /'test'.startsWith('\t')/  || false
        /'test'.startsWith('\c')/  || false
    }

Current opel implementation simply removes \ character leaving 't' or 'n' behind.

Let's handle \n,\t,\r explicitly.