Make JavaCompile cacheable in the presence of Xtext generator

Merge pull request #145 from xtext/issue_144

Use class instead of lambda

Kotlin DSL compatibility

Merge pull request #142 from sgarfinkel/master

#141 Replace Closure with Action<T>

Xtext 2.15 compatibility

Merge pull request #132 from xtext/cd_issue108_issue131

[#108][#131] ship custom IWorkspaceConfig to be compatible with multiple Xtext versions

Allow Xtext dependencies to be managed by BOMs

Merge pull request #126 from xtext/cd_exp

replaced detached configuration with explicit tooling configs so that customizations via resolution strategy and spring dependency plugin are possible

Gradle 5.0 compatibility

This release drops support for Gradle version < 4.3, but is now compatible with 5.0

Bugfix release

Merge pull request #106 from amityadav1/bug_105

Bug 105: IdeaPluginPlugin: Bug in collecting jars for ideaSandbox

Bugfix release

Merge pull request #102 from xtext/cd_issue101

[#101] Made Version Detection more robust regaring usage in java 9

Bugfix release

Merge pull request #93 from xtext/cd_fixDeps

implemented FilteringClassLoader.getResource to ensure isolation between plugin and build classloader

Gradle 3.5 compatibility

Merge pull request #85 from xtext/newWrapper

made plugin compatible with gradle 3.5 #84

Better backwards compatibility

Improve compatibility with older Xtext versions

Older Xtext versions did not declare the hard dependency from xtext.java
to jdt.core. To work around this we add the lowest compatible version of
jdt core to the runtime classpath and let Gradle do conflict resolution in
case a newer Xtext version needs a newer JDT version.