Class-Path manifest header

The change updates the java-main container to use the Class-Path
manifest header.  The container examines the application for that
header and if it exists, places all values from it on the classpath
when running the application.  To facilitate this, the properties
support was expanded to handle JAR manifest line-continuation
semantics.

[#52899629]
Merge 52899629-class-path to master

[Completes #52899629]
Play version

Previously, the detect output of the Play container was simply 'play'
without a version of the Play Framework being used.  As the detect
output is intended to be used to determine when applications a
susceptible to security exploits, it was important to output that
version.  This change attempts to determine the version by looking at
the Play JAR and extracting it's version number from it.

[#52855559]
Merge 52855559-play-version to master

[Completes #52855559]
Move Play detection into a utility module

The utility encapsulates the decision to search for Play applications
in the application root directory and its immediate children.

This utility is used by the Play container and will be used by the
Play auto-reconfiguration framework.

[#49696097]
Rename auto-reconfiguration framework

Since this framework is Spring-specific and we are about to introduce
a Play auto-reconfiguration framework, rename this to
SpringAutoReconfiguration at the risk of
floccinaucinihilipilification on the part of others.

[#49696097]
Merge branch '49696097-play-app-auto-reconfiguration' into glyn-master

Conflicts:
	lib/java_buildpack/container/play.rb