MNG-5676: Fix Maven crashing on IBM JDKs

ClassWorlds patch submitted by BJ Hargrave
fixed on 492acde3697f68efe78d0316278502d549782593
[MNG-5687] Parallel Builds can build in wrong order

Fixed JDK8 IT failure for MavenITmng3004ReactorFailureBehaviorMultithreadedTest#testitFailFastSingleThread

It turns out the execution order of the modules in the build can be incorrect, in some cases severely incorrect.
For parallel builds this can have all sorts of interesting side effects such as classpath
appearing to be intermittently incorrect, missing jars/resources and similar.

The -am options and -amd options may simply fail with the incorrect build order
because expected dependencies have not been built and actual dependencies may not have been built.

The underlying problem was that ProjectDependencyGraph#getDownstreamProjects and getUpstreamProjects
did not actually obey the reactor build order as defined by ProjectDependencyGraph#getSortedProjects,
even though the javadoc claims they should.

This has only worked by accident on earlier JDK's and might not have worked at all (basically
depends on Set iteration order being equal to insertion order). JDK8 has slightly different
iteration order, which caused the IT failure.

This problem may be the root cause of MNG-4996 and any other issue where the modules build
in incorrect order.

The bug affects:

parallel builds
command line -am (--also-make) option
command line -amd (also-make-dependents) option

On all java versions, although visibility might be somewhat different on different jdks.

Added simple unit test that catches the problem.
MNG-5695 fixed inconsistent/incomplete custom guice scope bindings

MojoExecution scope was only available for maven plugins and could not
be used for components defined in maven core or maven code extensions.

Session scope was only available for maven core and core extensions
but did not work for components from maven plugins.

Made both custom scopes available available in all realms.

Signed-off-by: Igor Fedorenko <ifedorenko@apache.org>
[MNG-5696] Remove dependency on Easymock

This closes #25
use latest plexus-utils bugfix
Account the the jsoup license URL which appears to have changed.

The JSoup license URL was recorded as http://jsoup.com/license but the
site appears to now be http://jsoup.org/ and so the URL is now
http://jsoup.org/license
Normalize all the line endings

Signed-off-by: Igor Fedorenko <ifedorenko@apache.org>
Revert "Account the the jsoup license URL which appears to have
changed." because https://github.com/jhy/jsoup/issues/471 fixed

This reverts commit 71f8d04be62b970dd730053bdf6b75ebaa04c8de.
[MNG-5700] Update p-int
updated parent pom (and fixed issues...)
Updated to p-u 3.0.20
[MNG-5707] warn if Maven unsupported slf4j binding used
[MNG-5712] improved toolchains descriptor documentation
[MNG-5713] improved Toolchains API description
[MNG-5713] fixed stupid typo due to JavaToolChain with C instead of c
[MNG-5715] Upgrade JUnit (for tests only)
upgrade from 3.8.2 to 4.11
Tweak the description for a PluginExecution phase, to clarify where the default phase comes from.
[MNG-5716] return toolchains that are of expected type
[MNG-5714] Add Merger for Maven Toolchain
implement equals() and hashCode() for DefaultToolchain to help the
Merger
remove unused import