Update the executable JAR code to automatically unpack any entries
which include an entry comment starting `UNPACK:` to the temp folder.
The existing Maven and Gradle plugins have been updated with new
configuration options and the `spring-boot-tools` project has been
updated to write the appropriate entry comment based on a flag passed
in via the `Library` class.

This support has been added to allow libraries such a JRuby (which
assumes that `jruby-complete.jar` is always accessible as file) to work
with Spring Boot executable jars.

Fixes gh-1070

Add a Library class update the LibraryCallback interface and
implementations to use it. This change is in preparation for
an addition `unpack` flag that will be required to allow the
automatic unpacking of certain nested jars.

See gh-1070

Update JarURLConnection to allow the resolution of items within a nested
jar, even if the jarFile passed to the connection is several levels up.

This prevent a connection from incorrectly resolving an entry against
the wrong jar file.

See gh-1070

Drop `RepackageTask.getDependencies` from the gradle plugin in favor of
exposing `getLibraries()` and using the callback.
Drop getDependencies

Extract the nasty Tomcat resource handling reflection code to its own
class.

Stretches the Gradle boot plugin a bit, so there's a sample build
in the "profile" sample. Howto docs give examples.

Fixes gh-1135

Fixes gh-1133

bean from the registration of Jackson modules to avoid circular creation
of the default ObjectMapper bean (and thus failing to obtain the ObjectMapper
and registering the module(s)).

Fixes gh-1132

See gh-1113

Tomcat 8 has different APIs again so it was quite difficult to
get it working and test it. The test is manual anyway (multi-module
project with JSPs in /META-INF/resources, not part of the samples),
and requires you to build a war and execute it (since the resource
paths are different when it's an archive).

Fixes gh-1131

Fixes gh-1130

See gh-1113

* document-remote-debug-gradle:
  Add how-to remote debug from Gradle

Add a section to the reference documentation "how-to" about remote
debugging a Gradle started app.

Fixes gh-1129

Improve fat JAR performance.

See gh-1119

Tweak 'fat jar' handling to generally improve performance:

- Allow JarURLConnection to throw a static FileNotFoundException when
  loading classes. This exception is thrown many times when attempting
  to load a class and is silently swallowed so there is no point in
  providing the entry name.
- Expose JarFile.getJarEntryData(AsciiBytes) and store AsciiBytes in
  the JarURLConnection. Previously AsciiBytes were created, discarded
  then created again.
- Use EMPTY_JAR_URL for the JarURLConnection super constructor. The URL
  is never actually used so we can improve performance by using a
  constant.
- Extract JarEntryName for possible caching. The jar entry name
  extracted from the URL is now contained in an inner JarEntryName
  class. This could be cached if necessary (although currently it is
  not because no perceivable performance benefit was observed)

Fixes gh-1119

Cache root jar files in the Handler and also store nested jar files in
the JarEntryData.

See gh-1119

Update JarFile to reuse the previously parsed entries when creating
filtered jars. This saves needing to re-scan the underlying file to
recreate a subset of entries.

See gh-1119

Drop JarEntryFilter arguments from the JarFile constructor and the
getNestedJarFile methods. Filtered JarFiles can still be obtained by
using the getFilteredJarFile() method.

This helps simplify the code a little and will make it easier to add
caching.

See gh-1119

Fix the formatting which was messed up in commit ad1636fd. Also
simplify the RabbitProperties.setVirtualHost logic a little

See gh-1128

The autoconfig strips out slashes where necessary to make a valid
hostname

Fixes gh-1128

(Was an attempt to get Cygwin to recognise the interrupt, but it seems
to be doomed so not worth having the extra code in there really.)

In order to solve issues with multiple or incompatible AccessDecisionManagers, the CRaSH integration will now only delegate to an explicit shellAccessDecisionManager bean refs #1121

It' sthe best we can do, but the container seems to still use our error page
(it just can't have the status code that we asked for).

Fixes gh-748

Fixes gh-1125

Adding an Order to the BeanPostProcessor and catching an exception
are enough to get a simple web app with @EnableGlobalMethodSecurity
and JDBC user details running. It actually doesn't solve an underlying
problem in Spring Security, but I'll deal with that separately.

See gh-1115