Move all lua related files to lua/ subfolder

Also remove the lexers sub directory from the Lua search path.
As a result we attempt to open fewer files during startup:

 $ strace -e open -o log ./vis +q config.h && wc -l log

In order to avoid having to modifiy all lexers which `require('lexer')`
we instead place a symlink in the top level directory.

 $ ./configure --disable-lua
 $ rm -rf lua

Should result in a source tree with most lua specifc functionality
removed.

1 files changed, 0 insertions, 64 deletions

diff --git a/lexers/gherkin.lua b/lexers/gherkin.lua
deleted file mode 100644
index c4f4dae..0000000
--- a/lexers/gherkin.lua
+++ /dev/null
@@ -1,64 +0,0 @@
--- Copyright 2015-2016 Jason Schindler. See LICENSE.
--- Gherkin (https://github.com/cucumber/cucumber/wiki/Gherkin) LPeg lexer.
-
-local l = require('lexer')
-local token, word_match = l.token, l.word_match
-local P, R, S = lpeg.P, lpeg.R, lpeg.S
-
-local M = {_NAME = 'gherkin'}
-
--- Whitespace.
-local ws = token(l.WHITESPACE, l.space^1)
-
--- Tags.
-local tag = token('tag', '@' * l.word^0)
-
--- Comments.
-local comment = token(l.COMMENT, '#' * l.nonnewline^0)
-
--- Strings.
-local doc_str = '"""' * (l.any - '"""')^0 * P('"""')^-1
-local dq_str = l.delimited_range('"')
-
-local string = token(l.STRING, doc_str + dq_str)
-
--- Placeholders.
-local placeholder = token('placeholder', l.nested_pair('<', '>'))
-
--- Keywords.
-local keyword = token(l.KEYWORD, word_match{
-  'Given', 'When', 'Then', 'And', 'But'
-})
-
--- Identifiers.
-local identifier = token(l.KEYWORD, P('Scenario Outline') + word_match{
-  'Feature', 'Background', 'Scenario', 'Scenarios', 'Examples'
-})
-
--- Examples.
-local example = token('example', '|' * l.nonnewline^0)
-
--- Numbers.
-local number = token(l.NUMBER, l.float + l.integer)
-
-M._rules = {
-  {'whitespace', ws},
-  {'comment', comment},
-  {'tag', tag},
-  {'placeholder', placeholder},
-  {'keyword', keyword},
-  {'identifier', identifier},
-  {'example', example},
-  {'string', string},
-  {'number', number}
-}
-
-M._tokenstyles = {
-  tag = l.STYLE_LABEL,
-  placeholder = l.STYLE_NUMBER,
-  example = l.STYLE_NUMBER
-}
-
-M._FOLDBYINDENTATION = true
-
-return M