[cogl-fixed] Add a double-to-fixed conversion macro
[cogl-fixed] Add a double-to-fixed conversion macro

Since the conversion of a floating point value to a fixed point
value is already done in double precision we can safely expose
a macro that converts a double precision floating point value to
a CoglFixed one.

Distrotech/cogl,djdeath/cogl-android,djdeath/cogl,Distrotech/cogl,gcampax/cogl,djdeath/cogl,collects/cogl,djdeath/cogl-android,djdeath/cogl,Distrotech/cogl,gcampax/cogl,gcampax/cogl,spatulasnout/cogl,gcampax/cogl,spatulasnout/cogl,djdeath/cogl-android,collects/cogl,Distrotech/cogl