Fix 'find' script

Add missing brace.
Fix 'gzip' script

  * :r added .gz to the buffer name (an untitled one became a mere .gz)
  * :e displayed the text in hex mode
  * :e didn't display in syntax (color) mode
  * saving didn't work due to a missing bang

Despite the note in the Announce file, :e worked better in the old
augz script (the former name of gzip), so the code around rerunning
"elvis.arf" has been removed again.
Fix and improve 'herefile' script

Following the << there can be an optional minus sign (not a backslash)
and whitespace.

Correct \\s.

Trigger OptChanged bufdisplay so that the here-files will be colored
immediately.
Add missing optinsert

This makes option 'includepath' available for the calculator
(and fixes the 'find' and 'sfind' aliases defined by likevim.ex).
Revise and edit syntax highlighting for elvis.syn

  * add missing keywords
  * all keywords (and comment) may appear at the beginning of a line
    after optional whitespace, so change anchor to ^
  * complete built-in and default face names not defined otherwise and
    define them with "font face" (instead of keyword, because they aren't
    keywords) in order to allow a user-defined coloring
  * color "font face" like keyword in order to behave as before
  * for backslash, prefer definition as keyword to string
  * add face string for 'none' appearing after 'backslash' as well as
    'normal' and 'formatted' appearing after 'mostly'
  * remove inword (there is no attribute with an underscore)
Improve syntax highlighting for language ex

  * add elvis.clr and elvis.x11
  * add missing ex commands and abbreviations
Fix documentation of ex commands

  * abbreviation of alias is ali, not al
  * add missing aue[vent] and doa[utocmd]
  * list nof[old] alphabetically
Correct comment in 'life' script
Correct 'mailto' script

Correct comment.

A signature consists of two hyphens followed by a space.
So add a space character.
Fix 'since' script

Fix the region face name in alias 'since' so that the region can be
colored.

Since colors orange and tan aren't commonly available, errors may occur.
Choose appropriate colors where they are missing.
Fix documentation on :sbrowse

Its abbreviation is sbr, not sb.
Improve scripts 'herefile', 'mail' and 'since'

Allow colors to be user-defined.