Added manual rotation of the ship rotation as discussed in issue #1156.
It is toggled on and off by a toggle button in ShipInfoCard. When in
manual rotation mode:

* Ship rotates up to certain speed. It keeps its motion until changed.
* When changing the speed of time flow, rotation is not stopped or
changed.

I'm new to this, so please tell me if I did something wrong, I'll try to
improve it next time.
Some corrections to manual rotation idea, issue #1156
* Time cannot be accelerated if rotating fast.
* Toggle button for manual rotation moved to constructor where it
probably belongs.
* Manual rotation works only in Manual control mode, this is ensured by
adding argument manualRotationAllowed in PollControls.
Some fixes:
* Thrusters were over-sensitive in higher time acceleration mode. Fixed.
Ang. velocity capping added also in manual rotation mode. However, if
you spin the ship in slower time acceleration mode and then switch to
higher one, ship does not slow itself - it would look weird.
alpha to all system objects
Mapped toggle manual rotation state to key 'r'. The button added as
proper member of the class.
>RGB>Alpha
Proper destructor for ToggleButton and Labels in ShipInfoPage.
Undo the destructor, it caused game to crash when ExitGame was pressed,
instead of going to the main screen. (Why?)
undo + alpha for planet background
star_a
star_a_giant
star_a_hyper_giant
star_b
all stars
Allow multiple government types to be added to a Faction

Lua Faction:govtype now adds the govtype to the Faction's govtypes list
rather than changing the faction's sole govtype.
Custom systems are now included in the first faction that has the
system's govtype in its list (essentially no change)
Standard systems take the first govtype of the faction they are a member
(used to take the Faction's sole govtype, taking the first was the
simplest for me to implement).
Federation Faction definition now includes 'Earth Colonial Government'
as well as 'Earth Democracy'. This should bring Barnard's star back into
the Federation fold.

Conflicts:
	src/Factions.cpp
Clean-up of Faction usage in Polit

Crime and legality methods now use StarSystem->GetFactionIdx() rather
than looking it up index via a link from govType retrieved from
StarSystem->GetSysPolit()
Removed Faction index from politDesc_t
Moved SysPolit::GetAllegianceDesc to StarSystem::GetAllegianceDesc
Pick System's govType randomly from Faction's govType list

No longer always picks first (last?) in the list.
New Faction::RollGovType method taking an MTRand makes the selection
(May need renaming?)
Removed code for setting get CustomSystem's based on its govType.
Added factionIdx member to CustomSystem in preparation for enabling
setting of CustomSystems Factions from Lua.

Conflicts:
	src/Factions.cpp
Handle Factions with no GovTypes better

Now picks at random from the list of all government types.
Allow Lua to set Faction of Custom Systems

Example system in data\systems\custom\05_rondel.lua
Faction::GetIndexOfFaction method could probably be done better by
someone more familar with C++
Distribute appropriate GovTypes among existing factions

Independent gets everything non-specific.
Federation gets EARTH* (except EARTHMILDICT maps to 'Military
Dictatorship' but doesn't say anything about Earth)
CIS gets CIS*
Red gets EMPIRE*