[Performance] Memory allocation reduction

[Jorma Rebane]

Using MTuner data from a short run of the game, we can drastically improve 0 A.D. core engine performance, by reducing the number of allocations in the detected hotspots.

For more information, check the Memory Performance thread on the forums.

<progress>, <memblock>, <total memops>, <stacktrace>
( ),		size 4, 	count 61320, 	modeldef.cpp:300
( ),		size 8, 	count 61320, 	modeldef.cpp:301
( ),		size 48,	count 42028, 	parser.cpp:246
( ),		size 36,	count 40866, 	guimanager.cpp:273 & 265
( ),		size 8, 	count 32749, 	modeldef.cpp:241
( ),		size 32,	count 27638, 	textrenderer.cpp:136
( ),		size 8,		count 21952, 	cgui.cpp:986
( ),		size 16,	count 21952, 	textrenderer.cpp:77
( ),		size 16, 	count 21952, 	shaderdefines.cpp:135
( ),		size 48,	count 21952, 	cgui.cpp:954
( ),		size 12,	count 20688, 	modelrenderer.cpp:635
( ),		size 112,	count 17325, 	guirenderer.cpp:388!)
( ),		size 108,	count 16896,	patchrdata.cpp:173
( ),		size 8,		count 14852, 	shaderdefines.cpp:116
( ),		size 48,	count 14154, 	font.cpp:33
( ),		size 36,	count 13230, 	patchrdata.cpp:1025
( ),		size 48,	count 12008, 	parser.cpp:981
( ),		size 24, 	count 9783, 	patchrdata.cpp:1025
( ),		size 8,		count 9645, 	modelrenderer.cpp:433
( ),		size 8,		count 8935, 	modelrenderer.cpp:698
( ),		size 48,	count 8265, 	cgui.cpp:916
( ),		size 48,	count 8144, 	parser.cpp:933
( ),		size 93,	count 7806, 	guitext.cpp:266
( ),		size 132, 	count 7806, 	cgui.cpp:689
( ),		size 132,	count 7806, 	cgui.cpp:800 & 855
( ),		size 12,	count 7072, 	modelrenderer.cpp:636
( ),		,			,				textrenderer.cpp:77
( ),		,			,				textrenderer.cpp:179
( ),		,			,				patchrdata.cpp:1052
( ),		,			,				guitext.cpp:210
( ),		,			,				terraintextureentry.h:75
( ),		,			,				patchrdata.cpp:192
( ),		,			,				cgui.cpp:675
( ),		,			,				texturemanager.cpp:150
( ),		,			,				texturemanager.cpp:153
( ),		,			,				texturemanager.cpp:511
( ),		,			,				texturemanager.h:136
( ),		,			,				parser.cpp:639
( ),		,			,				componentmanager.cpp:620