Test setup for JDK8 support.

Only Oracle provides builds for JDK8 atm, and there is no OpenJDK
build, so the setup is slightly different. Files have to be copied
manually from an installed JDK. For comparison purposes, an Oracle JDK7
option has been added too. This should be removed before merging to master.
Added switch to CommentsCatcher. Assumption, until proven otherwise is
that JDK8 behaves similar to JDK7.
Compiler options can now be specified for JDK 8 or JDK 6/7 or lower.

After this was finalized I realize that we might consider moving entirely
to String based options, instead of inferring the options from the
provided enum. This setup does have the benefit of throwing exceptions when
options are not present.
Refactored out references to TypeTags.

Instead they are retrieved
dynamically, with a pinch of caching during runtime. We already had some
fixes to make sure that compile time constanst were not inlined, but we
need to take into account that a lot of the Integer-based enums have
been replaced with actual enums.

Also, certain TreeMaker methods needed to be invoked dynamically with
reflection.

This needs to be reviewed, and if it turns out that these changes are too
dramatic, we should fork out a larger part of our code for specific JVM
versions.
Fixed small typo
Some small fixes for Java 7
Type fixes for JDK7
Updated website; the footer of the video was too long and caused wonky formatting, and the download page now points to the IntelliJ plugin page instead of saying that IntelliJ doesn't support lombok.
Added a method to obtain latest java language spec supported by host
platform and implemented it for javac BUT NOT FOR ECJ!
Added methods to obtain JLS support-level version information from AST/LombokNode. Tests updates to honour these with //version X at the top
of any test file (now also in eclipse, which until now always said it was v6)
Fixed more issues related to java7's try-with-resources,
and updated ECJ version detection.
added previous fix of issue 520 to the changelog
whoops, didnt update version number to 0.11.9 yet
added test case and delombok result for issue 520 (val in try-with-resources). WARNING: I havent added ecj test output yet because so far there is no ecj7 available for testing with our buildscripts. I should fix that first and then Ill sort this out.
Fixes for issue 470: VerifyErrors when using @SneakyThrows.
Added @NonNull on parameters feature (issue 514),
including docs and changelog.
Added some very limited reporting when OutOfMemorErrors occur during
parse tree builder under javac. Let's hope our users reporting these
issues can use this to figure out which files are triggering the issue.
issue 536: annotationprocessor now always returns false.
Removed a SuppressWarnings which old eclipse doesn't care about for some reason... now I'm just confused. Do we need it or not?
Added injectType methods to Eclipse/JavacHandlerUtil, which we'll need to inject the created $Builder type.

Inspired by Philipp Eichhorn's work in lombok-pg.