Warning due to Implicit Type Conversion in graphene-simd4x4f.h

[PeterGriffinSr]

A compiler warning occurs in graphene-simd4x4f.h (line 659) due to an implicit type conversion from float to double:

if (fabs (graphene_simd4f_get_z (up) - 1.0) < FLT_EPSILON)

This causes the -Wdouble-promotion warning.

Suggested Fix:
To avoid this warning, cast the operands to double:

if (fabs ((double)graphene_simd4f_get_z(up) - (double)1.0) < (double)FLT_EPSILON)

Note:
This is just a warning and does not impact functionality if left unfixed.