names: Profile generation time of the star names

It is known that generating star names is strangely slow.  We could
make it faster.  But first we must measure the execution time to pin
down the cause of this inefficiency.
names: Defer logging name generation time at termination of the program

Still we are not sure about the problem cause.  It's common that debug
output process itself is making the program slow.  We try to minimize
the load of debug output by deferring execution of writing the profile
to a file until program termination.
names: Get rid of lambda expression in doubt about performance

C++'s lambda expressions are powerful tool that shortens many lines of
codes, but if it's making the program slow, we should avoid using it.
We are performing real-time, time-critical task to generate random names.
We should complete the task in a instant or process in parallel to
prevent freezes in the main game.

Now, it isn't making noticeable difference after getting rid of them.
names: Introduce DB of first 3 characters to enhance performance

The first 3 characters are picked from distinct set of sequences from
arbitrary 3 character sequence that can appear anywhere in a word.
Separating the first syllable indices to dedicated database (std::map)
may improve performance.

Now it's not making significant difference.
names: Get rid of debug outputs for the name generator
names: Greatly improve performance by using bsearch for name generation

That has been a long roundabout to find a obvious answer.
The cause of the inefficiency is that we haven't using correct algorithm.
names: Share struct for syllables to compact codes
names: Centralize definition of StarEnum's sectorSize

Also renamed the constant from cellsize to sectorSize.  The new name
seems to be more meaningful.

Also fixed a minor incorrectness in type of StarEnum::cen from Vec3d to
Vec3i.
Fix a bug in calculation of desired velocity in warping
names: Enable Warpables to warp to randomly generated stars

If you approach a randomly generated star, you'll notice that it's just
a sprite without body.
names: Approaching a random star make it materialize

The materialized star is the same as other stars like Sol or Alpha
Centauri.

Also addressed light direction vector being zero vector in such a
star system.