[xbase][lib] Marked bitwise operators as contantExpressions

Adjusted the compiler to respect those, too such
that bitwise stuff can be used in annotation values

see https://bugs.eclipse.org/bugs/show_bug.cgi?id=443874

Change-Id: Id0827ceb1558816badc8db94267111d2a8c4ceb3

Conflicts:
	tests/org.eclipse.xtend.core.tests/src/org/eclipse/xtend/core/tests/compiler/AnnotationCompilerTest.xtend
	tests/org.eclipse.xtend.core.tests/xtend-gen/org/eclipse/xtend/core/tests/compiler/AnnotationCompilerTest.java
[xbase][typesystem] Fixed IAE with var arg methods invoked as extension

see https://bugs.eclipse.org/bugs/show_bug.cgi?id=450354

Change-Id: Icacd4bb8a0891ee6ccd9863e35e356d7339b44de
Merge "[xbase][lib] Marked bitwise operators as contantExpressions" into v2.7_Maintenance
Merge "[xbase][typesystem] Fixed IAE with var arg methods invoked as extension" into v2.7_Maintenance