Better project files.

- Output directly to rel\ instead of to bin\ and then copying files over.
- Deduped Win32 vs x64 configs
- Moved some common properties to hexchat.props
- All build intermediates (except htm's intermediates) are no longer emitted in the source directory

src/fe-gtk/hexchat.rc.tt

@@ -1,9 +1,9 @@
 #include <winver.h>
-#include "../../config.h"
+#include "config.h"
 
 #define COMMA_VERSION <#= [string]::Join(',', $versionParts) #>,0
 
-XC_ICON ICON "../../data/icons/hexchat.ico"
+XC_ICON ICON "<#= $env:SOLUTIONDIR -replace '\\', '/' #>data/icons/hexchat.ico"
 
 VS_VERSION_INFO VERSIONINFO
 	FILEVERSION    COMMA_VERSION