v0.18: Balance rare cards, new UI options

This update incorporates expensive balance changes based on playtesting and player feedback. In particular, clairvoyance status is now significantly more useful, with new cards and items benefiting from it, as well as new quests with clairvoyance-related rewards.

Many other rarely used cards were updated to make them either stronger or easier to use. For example, previously awkward interaction when Rite of Legacy preserved reduced Persist counter on Ritual Circle is now removed by making Ritual Circle's Persist conditional instead of counted.

Multiple UI options and minor improvements are targeted to address various players preferences.

Major gameplay changes:

• Rework of 'clairvoyance' status. Now it is reduced by number of actual cards drawn, not cleared at the end of turn
  • Makes it possible to compound clairvoyance over several turns

Minor UI changes:

• Added more keywords / hints
• More improved card and item sprites by @MovingTheMovingPictures
• More terrain tiles by @MovingTheMovingPictures
• Documented special symbols in formulas and status descriptions
• Added option display hint window for cards in hand only on keypress
• Added option to play cards with a single click
• Added options to show/hide titles of cards in hand and monsters on the field
• Improved setting window styling
• Added 'search draw/discard pile' line to hint windows of some cards and items
• Highlighted formulas in effect descriptions
• Optimized terrain tiles rendering on slow Internet connections

New cards (3):

• Prophesy of Doom, Illusory Arsenal, All In

New items (2):

• Crystal Eye, Double Neck Flask

New quests (7):

• 'Old temple: Serve as herald of war'
• 'Old temple: Pray to become herald of war'
• 'Merchant guild: Sell off your goods'
• 'Darkwood: Hunt rabbits'
• 'Casino: Play matching game'
• 'Nether planes: Gaze into next hour'
• 'Nether planes: Steal enemy visions'

Balance and miscellaneous changes:

• Buffed cards (23):
  Avatar of War, Austerity, Sermon, Charity, Extract Essence, Addiction,
  Adrenaline, Smith Weapons, Cleave, Double Shot, Decoy, Gather Pebbles,
  Fencing, Factory Layout, Mechanical Arm, Poisoned Dagger, Parry. Pure Reason,
  Rite of Aegis, Rite of Famine, Rite of Pain, Rite of Vengeance, Rite of Legacy
• Nerfed cards (4):
  Coffee, Quiet Chant, Stasis, Visions of the Future
• Rebalanced cards: Ritual Circle, Threatening Shout
• Rebalanced items: Bag of Coins, Whetstone, Crystal Orb
• Clarified card descriptions:
  Charity, Ad Infinitum, Circle of Blood, Addiction, Forge Sword, High Roll,
  Polymorph, Push, Knockback, Grappling Hook, Taunt
• Clarified upgrade effect description
• Clarified some item descriptions
• Moved 'Embark on spiritual journey' quest from 'Old temple' to 'Secluded retreat' location
• Quests requiring some effect as prerequisite now accept effect on items in addition to cards
• Renamed Study card to Learn

Selected bugfixes:

• Fix display of upgrade limit when last upgrade removes effect
• Fix Iron Purse not affecting 'Merchant guild: Make investment' quest
• Fix descriptions of Clay Mold and Masquerade Mask items