More properties and cleanup

src/commonMain/kotlin/nl/astraeus/css/properties/CssProperty.kt

@@ -0,0 +1,17 @@
+package nl.astraeus.css.properties
+
+open class CssProperty(
+    val value: String
+) {
+    fun css(): String = value
+
+    open fun validate() {}
+
+    open fun validateMultiple(props: List<*>) {}
+}
+
+fun text(value: String) = TextProperty(value)
+
+class TextProperty(
+    value: String
+): CssProperty(value)