TTF font support

[Jed-]

TTF font and Unicode support

All text is now rendered with TTF fonts using pangocairo, and UTF-8 strings are supported natively.

Add a dependency on pango >= 1.56.
On Linux, the game can alternatively be compiled against pango >= 1.38 and fontconfig by adding -DOLDPANGO as a compiler flag.

Bump the minimum standard version to C++11.

Player names are restricted to a subset of Latin, Cyrillic and Greek characters in order to prevent abuse. The rest of the UI, console and particles can use any set of Unicode characters without restriction. If two player names are visually identical or very similar, they are marked as duplicates even if the actual string are different.

In addition to the color codes \f0 through \f9, more codes have been added to support basic markup:

• \fb...\fB = bold
• \fi...\fI = italic
• \fu...\fU = underline
• \ft...\fT = strikethrough
  where ... is the part of the string to apply the markup to.

The colors corresponding to \f codes can now be customized with the textcolor command.

Using TTF fonts:

• each TTF file must be registered with the registerfont command before it can be used
• the font command is used to define a font family to use in-game
• several commands are available to customize each font, see config/font.cfg for how to use them
• the fontalias command has been removed

Console changes:

• add variable conshadow (0, 255, 255): adds a black shadow to console text for increased visibility
• add variable conoutline (0, 0, 255): adds a black outline around console text
• change the range of conscale from (0.001, 0.45, 1000) to (0.5, 1, 2)

Command line changes:

• add the cursorblink (0, 750, 2000) variable to customize the cursor's blink speed (0 = disable blinking)
• add the cursorcolor (0xFFFFFF) variable to customize the cursor's color
• the cursor does not blink while the user is typing
• the resetcursorblink command can be used to stop the cursor blink animation for a short time

Text particle changes:

• the function particle_text() now accepts font and language arguments
• add function particle_hud_text(): renders a text particle as a hud mark, similar to particle_hud_mark(), this is now used to render the GOAL label in CTF mode

UI changes:

• remove variable uitextrows; UI text scale can still be configured with uiscale
• add variable uifps (0, 60, 1000): controls how often text elements check for text changes (0 = check every frame, may impact performace)
• add several UI commands to customize text elements, which can be nested
• text elements can now read keyboard and mouse input

New UI commands:

• uiwrapalign -1|0|1 [children]: sets the alignment for multi-line paragraphs (-1 = left, 0 = center, 1 = right)
• uijustify 0|1 [children]: controls justification for multi-line paragraphs
• uishadow alpha [children]: draw a transparent black shadow behind the text (alpha from 0 to 255)
• uifontoutline thickness alpha [children]: draw a transparent black outline around the text (thickness is expressed in 1/16ths of the current font height; alpha from 0 to 255)
• uinofallback 0|1 [children]: disable falling back to system fonts for unavailable characters
• uilanguage lang [children]: specify the language of the text, which can affect text shaping (lang must be a string in RFC-3066 format)
• example usage:

newui test [
  uilanguage "en" [
    uishadow 0xFF [
      uiwrapalign 0 [
        uijustify 1 [
          uiwraptext "Lorem ipsum dolor sit amet" 0.5 3
        ]
      ]
    ]
  ]
]

Global font settings (users may change these to their liking):

• fontantialias (0, 1, 1): toggle font antialiasing (only grayscale antialiasing is supported)
• fonthinting (-1, -1, 3): set font hinting (-1 = system default, 0 = disabled, 1 = slight, 2 = medium, 3 = full)

Settings for individual fonts (to use after the font command, refer to config/font.cfg):

• fontweight [-3..6]: < 0 = lighter, > 0 = bolder
• fontstretch [-4..4]: < 0 = tighter, > 0 = wider (many fonts don't support this)
• fontstyle [0..2]: 0 = normal, 1 = oblique, 2 = italic
• fontsmallcaps 0|1
• fontfeatures [...features]: OpenType features, in CSS font-feature-settings format
• fontvariations "variations": for OpenType variable fonts, format: "AXIS1=VALUE,AXIS2=VALUE..."

Other added commands:

• strbytelen str: returns the length of a string, in bytes
• char2byteindex str ix: converts a character index to a byte index
• byte2charindex str ix: inverse of the above

Miscellaneous changes:

• change the filtertext function to take a flags argument rather than a series of booleans
• remove the tabify and textbright commands
• remove the tessfont tool