Add "Compact HUD" setting

Enable in your rcfile with `compact_hud = true`.

Basically, lots of items have been shuffled around and/or redesigned for a
more compact interface look-and-feel. Right now, this saves three full
lines. Those lines go straight into monster list which in 80x24 can now
take up to 7 lines, up from the previous 4.

Information loss compared to "traditional" mode:
- HUD no longer shows player gold (press $ for your shopping list)
- amount of HP rotted (there is, however, a rot indicator)
- no way of seeing the "Time:" value previously displayed on-screen,
  which mostly is the sum of all player actions expressed in aut
All of these can still be accessed from the % screen as well.
- in wizard mode, GDR of currently worn armour

Information present now that is not in "traditional" mode:
- both duration of last player action (in aut) and duration of game (in
  scoring turns)

Traditional HUD layout:
| wizard the Spellbinder            *WIZARD* |
| Mottled Draconian of the Shining One**.... |
| Health: 113/181   ==============---------- |
| Magic:  16/16     ======================== |
| AC:  3(0%)        Str: 4                   |
| EV: 18            Int: 15 (16)             |
| SH:  0            Dex: 16                  |
| XL: 20 Next: 81%  Place: Orcish Mines:1    |
| Gold: 2436        Time: 17190.2 (0.7)      |
| a) +6 spear {reap, Hex rPois rN+ HP-6}     |
| -) Nothing quivered                        |
| Engorged                                   |
|                                            |
| ee  2 deep elf blademasters                |
| ee  2 deep elf master archers              |
| ee  2 deep elf annihilators                |
| ee  3 deep elf demonologists           (…) |

New compact HUD layout:
| wizard the Spellbinder            *WIZARD* |
| Mottled Draconian of the Shining One**.... |
| H 113/181 M 16/16 ==============---------- |
| AC  3   Str  4    ======================== |
| EV 18   Int 15+1  XL 20.81  Orcish Mines:3 |
| SH  0   Dex 16    @   0.7   Turns 19704    |
| a) +6 spear {reap, Hex rPois rN+ HP-6}     |
| f) 10 stones                               |
| Engorged                                   |
|                                            |
| ee  2 deep elf blademasters                |
| ee  2 deep elf master archers              |
| ee  2 deep elf annihilators                |
| ee  3 deep elf demonologists               |
| e  5 deep elf knights                      |
| e  5 deep elf summoners                    |
| o  2 orcs                              (…) |
Skill bar in HUD (mauris)

Enable with `show_skill_bar = true` and `compact_hud = true` in your rcfile.

Adds one line to the HUD, thus is only available in compact mode for now.
This new line lists the skills currently enabled for training alongside
their respective level.

An example:
    Dodging*1.7  Stealth 3.2  Axes 0.0

The skill bar can fit up to four skills. If more than four skills are
enabled for training, the first four are displayed and an ellipsis
(like in the monster list) indicates that there is more to see.

Skills are sorted by skill level in decreasing order. Focused skills
appear before non-focused ones, and are marked with a trailing asterisk.

Skill names will be abbreviated to three or four characters each in case the
full skill names do not fit the HUD. An example of this and the ellipsis:
    Dod*10.1  Ste 24.4  Fgt 2.0  Axe 0.0   (…)

The short skill name abbreviations try to stick close to the ones the manual
uses (?%), but some have been slightly adjusted. A few of them use four-char
abbreviations. In very rare corner cases this could lead to the last skill's
decimal place being overwritten by the ellipsis. Those cases of course will
become more common if more skills were to use four chars instead of three.
I believe the current set is a fair trade-off between interface constraints
and usability.