bump the Eclipse compile source to Java 1.8

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1813840 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -113,7 +113,7 @@ org.eclipse.jdt.core.compiler.problem.unusedPrivateMember=warning
 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.source=1.7
+org.eclipse.jdt.core.compiler.source=1.8
 org.eclipse.jdt.core.formatter.align_fields_grouping_blank_lines=2147483647
 org.eclipse.jdt.core.formatter.align_type_members_on_columns=false
 org.eclipse.jdt.core.formatter.alignment_for_arguments_in_allocation_expression=16