Added useful optional arguments to bItalic().

The parameters are:
    1. Italic angle (as implemented previously).
    2. Italic xheight, as a fraction of the font xheight.
    3. Flags: an integer composed of the following bit values:
       * 0x0001 = Transform bottom serifs.
       * 0x0002 = Transform serifs at x-height.
       * 0x0004 = Transform serifs on ascenders.
       * 0x0008 = Transform diagonal serifs.
       * 0x0010 = Create italic a from the bottom half of italic d.
       * 0x0020 = Give italic f a long tail.
       * 0x0040 = Give italic f a hook.
       * 0x0080 = Remove serifs from descenders.
       * 0x0100 = Special handling for Cyrillic phi.
       * 0x0200 = Special handling for Cyrillic i.
       * 0x0400 = Special handling for Cyrillic pi.
       * 0x0800 = Special handling for Cyrillic te.
       * 0x1000 = Special handling for Cyrillic sha.
       * 0x2000 = Special handling for Cyrillic dje.
       * 0x4000 = Special handling for Cyrillic dzhe.
    4. Serif type: 1=flat, 2=simple slant, 3=complex slant.
    5. LSB change: left bearings will be multiplied by this factor.
    6. Stem width change: stem widths are multiplied by this factor.
    7. Counters change: counters will be multiplied by this factor.
    8. Stem width change for lowercase characters; defaults to #6.
    9. Counters change for lowercase characters; defaults to #7.
Documented the Italic() native scripting function.
Merge pull request #1054 from blipvert/fixes/20

Added useful optional arguments to the Italic() native scripting function