Update the "Supported Platforms" list for Qt 4.7 and 4.8

The following correction need to be made to the "Supported Platforms" list for Qt 4.7:

• msvc2003 is now Tier 2 and support for it is deprecated
• Mac g+ needs to be change to: Mac g+ (Cocoa and Carbon)
• Solaris, AIX, HPUX are supported by a third party; Digia (to be confirmed).
• VXWorks and QNX ports of Qt are supported by the OS vendors
• Intel compiler (icc) on Linux is supported to the extent of compilation testing in Qt test infrastructure.

Re Qt 4.8 since supported platforms is not yet determined provide a "minimalist Tier1" list and put comments that the list is subject to review.