Code review comment for lp://staging/~dbarth/unity-2d/envvar-jit-flag

If you're not going to use the "jit-composite" dconf key any more, you should remove it from both places in spread/app/spreadview.cpp, and from the schema.

I would also prefer reading UNITY2D_JIT_COMPOSITE in the SpreadView constructor to set a private boolean member of the class, which can be used throughout the lifetime of the spread. Env var can't be changed during runtime, so it avoids useless repeated reads.

qDebug() needed?