Added support for configuring gpg's passphrase, key id and secret key ring location via local.properties.

modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/maven/Gpg.kt

@@ -1,16 +1,18 @@
 package com.beust.kobalt.maven
 
 import com.beust.kobalt.OperatingSystem
+import com.beust.kobalt.misc.LocalProperties
 import com.beust.kobalt.misc.error
 import com.beust.kobalt.misc.kobaltLog
 import com.beust.kobalt.misc.warn
+import com.google.inject.Inject
 import com.google.inject.Singleton
 import java.io.BufferedReader
 import java.io.File
 import java.io.InputStreamReader
 
 @Singleton
-class Gpg {
+class Gpg @Inject constructor(val localProperties: LocalProperties) {
     val COMMANDS = listOf("gpg", "gpg2")
 
      fun findGpgCommand() : String? {
@@ -42,9 +44,30 @@ class Gpg {
                 ascFile.delete()
                 val allArgs = arrayListOf<String>()
                 allArgs.add(gpg)
+
+                val pwd = localProperties.getNoThrows("gpg.password")
+                if (! pwd.isNullOrBlank()) {
+                    allArgs.add("--passphrase")
+                    allArgs.add(pwd)
+                    allArgs.add("--batch")
+                    allArgs.add("--yes")
+                }
+
+                val keyId = localProperties.getNoThrows("gpg.keyId")
+                if (! keyId.isNullOrBlank()) {
+                    allArgs.add("--local-user")
+                    allArgs.add(keyId)
+                }
+
+                val keyRing = localProperties.getNoThrows("gpg.secretKeyRingFile")
+                if (! keyRing.isNullOrBlank()) {
+                    allArgs.add("--secret-keyring")
+                    allArgs.add("\"$keyRing\"")
+                }
+
                 allArgs.add("-ab")
                 allArgs.add(file.absolutePath)
-
+                
                 val pb = ProcessBuilder(allArgs)
                 pb.directory(directory)
                 kobaltLog(2, "Signing file: " + allArgs.joinToString(" "))