Added GamePhase api

src/main/kotlin/net/axay/kspigot/game/GamePhasesBuilder.kt

@@ -0,0 +1,42 @@
+@file:Suppress("MemberVisibilityCanBePrivate")
+
+package net.axay.kspigot.game
+
+class GamePhaseSystemBuilder {
+
+    private val gamePhases = mutableListOf<GamePhase>()
+    fun build() = GamePhaseSystem(*gamePhases.toTypedArray())
+
+    fun phase(length: Long, builder: GamePhaseBuilder.() -> Unit) {
+        gamePhases += GamePhaseBuilder(length).apply(builder).build()
+    }
+
+}
+
+class GamePhaseBuilder(val length: Long) {
+
+    private var start: (() -> Unit)? = null
+    private var end: (() -> Unit)? = null
+    private var counterMessage: ((secondsLeft: Long) -> String)? = null
+
+    fun start(callback: () -> Unit) {
+        start = callback
+    }
+
+    fun end(callback: () -> Unit) {
+        end = callback
+    }
+
+    fun counterMessage(callback: (secondsLeft: Long) -> String) {
+        counterMessage = callback
+    }
+
+    fun counterMessage(prefix: String, beginning: String, seconds: String, second: String) {
+        counterMessage = net.axay.kspigot.game.counterMessage(prefix, beginning, seconds, second)
+    }
+
+    fun build() = GamePhase(length, start, end, counterMessage)
+
+}
+
+fun buildGame(builder: GamePhaseSystemBuilder.() -> Unit) = GamePhaseSystemBuilder().apply(builder).build()