Fix Issue 1553 - foreach_reverse is allowed for delegates

http://d.puremagic.com/issues/show_bug.cgi?id=1553
Issue 5498 - array of elements of subtypes of a common supertype

arrayExpressionsToCommonType incorrectly uses condexp.e2->type rather than condexp.type to determine the common type of the array.
fix Issue 4757 - A forward reference error with return of inner defined struct
Fix crash with non-normalized Windows paths in Visual Studio build
fix Issue 12302 - Assertion failure in expression.c (line 432) when using template isCallable
Merge pull request #3366 from CyberShadow/fix12302

fix Issue 12302 - Assertion failure in expression.c (line 432) when using template isCallable
Merge pull request #684 from yebblies/issue5498

Issue 5498 - array of elements of subtypes of a common supertype
[style] fix indent
fix Issue 12334 - Cannot access frame pointer of nested class from inside lambda
fix Issue 12280 - Redundant "template instance ... error instantiating" messages
Improve error diagnostic in fail_compilation/ice10076.d
Merge pull request #3368 from CyberShadow/vs-20140309

Fix crash with -main and non-normalized Windows paths in Visual Studio build
Merge pull request #3373 from 9rnsr/fix12280

Issue 12280 - Redundant "template instance ... error instantiating" messages
Add Makefile rule for generating Exuberant Ctags tags file
Scan C++ headers (.h) aswell when generating tags
Fix layout and ECTAGS_FILES
Merge pull request #184 from yebblies/issue1553

Issue 1553 - foreach_reverse is allowed for delegates
partial fix for Issue 5570
Merge pull request #3372 from WalterBright/fix5570

partial fix for Issue 5570
Fixes Issue 648 - Document template mixin instantiations.