Plasmaeffect example: Disable vertex attributes if not used

This fixes a crash that may occur on some hardware

Change-Id: I603352ce625ea01f977ff0ca19b1c64ae003d3c1
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>
Use delete [] operator for arrays

This commit also fixes a memory leak occurring because of
non-deleted char arrays

Change-Id: Ic3e1dac213726e60a659a1362d64512a8867f788
Reviewed-by: Tomi Korpipää <tomi.korpipaa@digia.com>
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>
Use proper multiline strings for shader strings

Added to the rest of the examples. Causes crashing on Qt5.4 Beta without
them.

Change-Id: I7b060ccdfd5458057dd3053ca40d8569aef89dd2
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>