syntax coloring: added markdown & awk; removed regexp

Added rules for markdown and awk coloring.  Markdown just colors
section headers.

Regex coloring was problematic, so I removed it.

	modified:   src/editor.rb
	modified:   src/syntaxcolors.rb
bugfix: several syntax colorin bugs

1. Regex handling was wrong. Had to write my own method for converting
strins to regex.

2. Color codes were being chopped off. Terminal's write_line was not
grabbing the ending escape codes, and thus sometimes leaving colors
open on the screeen.

3. Fixed trailing whitespace coloring. It was requireing a color
sequence at the end of the line, because we used to always append
$color[:normal] to every printed line.  We no longer do that, so we
must allow for no color code at the end of the line.  We should have
done before anyway.

	modified:   src/antsy.rb
	modified:   src/syntaxcolors.rb
	modified:   src/utils.rb
cleanup: minor changes to doc and example config

doc: changed "editor" to "jedi" in a few places

config: commented out entire example config file, so everything is at
default

	modified:   README.md
	modified:   doc/jedi.1
	modified:   doc/manual.md
	modified:   scripts/config.rb
bugfix: fixed handling of regexp search terms.

I moved to_regexp to the utils.rb, and set the text_buffer searcher to
not care if it is a regexp or not.  Only the file_buffer cares to
check.

	modified:   src/filebuffer.rb
	modified:   src/textbuffer.rb
bugfix: must check for nil, before running match.

The previous change which has search/replace check for regex didn't
check for nilness before asking it token was a regexp.  This crashed if
the user cancelled the search.

	modified:   src/filebuffer.rb
bugfix: previous changes to search/replace must apply to search

Changes made to fix search/replace broke search.

	modified:   src/filebuffer.rb
bugfix: was crashing for folded text when window was very narrow

Check for nil in sample folded text string.

	modified:   src/filebuffer.rb
bugfix: set default parameter value in string.to_regexp

	modified:   src/utils.rb
bugfix: some mysterous bugs

I  put in some checks, and it seems to work, but there are some
mysterious things happening with buffer history.

	modified:   src/bufferhistory.rb