Bug 435922 - PHP 5.6 support

Conflicts:
	plugins/org.eclipse.php.core/src/org/eclipse/php/internal/core/ast/nodes/AST.java
	plugins/org.eclipse.php.core/src/org/eclipse/php/internal/core/codeassist/PHPSelectionEngine.java
	plugins/org.eclipse.php.core/src/org/eclipse/php/internal/core/codeassist/contexts/UseConstNameContext.java
	plugins/org.eclipse.php.core/src/org/eclipse/php/internal/core/codeassist/contexts/UseFunctionNameContext.java
	plugins/org.eclipse.php.core/src/org/eclipse/php/internal/core/codeassist/strategies/GlobalConstantsStrategy.java
	plugins/org.eclipse.php.core/src/org/eclipse/php/internal/core/codeassist/strategies/GlobalFunctionsStrategy.java
	plugins/org.eclipse.php.core/src/org/eclipse/php/internal/core/codeassist/strategies/UseNameStrategy.java
	plugins/org.eclipse.php.ui/src/org/eclipse/php/internal/ui/editor/contentassist/PHPCompletionProposalCollector.java
	plugins/org.eclipse.php.ui/src/org/eclipse/php/internal/ui/editor/contentassist/UseStatementInjector.java
	tests/org.eclipse.php.ui.tests/workspace/codeassist/php56/useFunction01.pdtt
	tests/org.eclipse.php.ui.tests/workspace/codeassist/php56/useFunction02.pdtt

Change-Id: I5933c027352071cab2a8dc79060a1f82f819df77