Multiple fixes and enhancements

[gorky]

Fixes:

• Background Process Hangs When There's Too Much Unprocessed Output. See https://github.com/marc0der/gradle-spawn-plugin/issues/30
• https://www.securecoding.cert.org/confluence/display/java/FIO07-J.+Do+not+let+external+processes+block+on+IO+buffers

Enhancements

• timeout: Allows a timeout to be set for when a process should be started/stopped
• siphon: Some processes will react to stdout being closed as a "Stop/Terminate" signal. Setting this property will allow for the Spawn thread to continue running and pulling stdout after a "Ready Match". This is useful in case there are other long running processes being run/launched by Gradle.

Possible fixes for: Process does not continue #29 https://github.com/marc0der/gradle-spawn-plugin/issues/29 Spawn doesn't catch failed tasks https://github.com/marc0der/gradle-spawn-plugin/issues/8

Available to use for testing/etc from https://bintray.com/gorky/gradle-plugins/gradle-spawn-plugin.

Released under the original Apache 2.0 license.