Backport all build-related commits from master to stable-0.2

This is a squash of the following commits that are required to
make gitiles buildable with the latest bazel:

9374f0a - Remove bazel-genfiles from .gitignore
bd0c596 - Use bazelisk as first choice for mvn.sh
9d5cb21 - Replace references to bazel-genfiles with bazel-bin
268d677 - Bazel: Bump bazel version to 1.0.0
03cd750 - Bazel: rules_python must be loaded now
10641da - Upgrade bazlets to latest master revision
06d3ee0 - Bazel: Introduce .bazelversion and update to 0.29.1
3de4f96 - Format all build files with buildifier
a267c30 - Bazel: Add fixes for --incompatible_load_java_rules_from_bzl
4d4432d - Upgrade bazlets to latest master revision
422d67a - Align Eclipse settings with Eclipse 2019.06
008bf1b - Update bazlets to latest revision on master

Change-Id: I4894d7beee21a0ea4bfd92c6ce3c6bf6477ef639

.settings/org.eclipse.jdt.core.prefs

diff --git a/.settings/org.eclipse.jdt.core.prefs b/.settings/org.eclipse.jdt.core.prefs
index 738ff3f..db7a8d9 100644
--- a/.settings/org.eclipse.jdt.core.prefs
+++ b/.settings/org.eclipse.jdt.core.prefs
@@ -24,6 +24,7 @@
 org.eclipse.jdt.core.compiler.problem.deprecationWhenOverridingDeprecatedMethod=disabled
 org.eclipse.jdt.core.compiler.problem.discouragedReference=warning
 org.eclipse.jdt.core.compiler.problem.emptyStatement=warning
+org.eclipse.jdt.core.compiler.problem.enablePreviewFeatures=disabled
 org.eclipse.jdt.core.compiler.problem.enumIdentifier=error
 org.eclipse.jdt.core.compiler.problem.explicitlyClosedAutoCloseable=warning
 org.eclipse.jdt.core.compiler.problem.fallthroughCase=warning
@@ -80,6 +81,7 @@
 org.eclipse.jdt.core.compiler.problem.redundantSuperinterface=ignore
 org.eclipse.jdt.core.compiler.problem.reportMethodCanBePotentiallyStatic=ignore
 org.eclipse.jdt.core.compiler.problem.reportMethodCanBeStatic=ignore
+org.eclipse.jdt.core.compiler.problem.reportPreviewFeatures=warning
 org.eclipse.jdt.core.compiler.problem.specialParameterHidingField=disabled
 org.eclipse.jdt.core.compiler.problem.staticAccessReceiver=warning
 org.eclipse.jdt.core.compiler.problem.suppressOptionalErrors=disabled
@@ -112,6 +114,7 @@
 org.eclipse.jdt.core.compiler.problem.unusedTypeParameter=ignore
 org.eclipse.jdt.core.compiler.problem.unusedWarningToken=warning
 org.eclipse.jdt.core.compiler.problem.varargsArgumentNeedCast=warning
+org.eclipse.jdt.core.compiler.release=disabled
 org.eclipse.jdt.core.compiler.source=1.8
 org.eclipse.jdt.core.formatter.align_type_members_on_columns=false
 org.eclipse.jdt.core.formatter.alignment_for_arguments_in_allocation_expression=16