Gemification: Basic structure and options

 - Rearranges files to conform to Gem structure.
 - Add requisite meta data.
 - Rearrange engines, extensions, log writers into (sub)modules.
 - Component lists are now static instead of defined by folder content.
 - Introduce name 'chew'

Starts on issues #93, #96, #98.

Gemfile

@@ -1,6 +1,4 @@
-source 'https://rubygems.org'
+# frozen_string_literal: true
 
-gem 'listen'
-gem 'parallel'
-gem 'ruby-progressbar'
-gem 'tex_log_parser'
+source 'https://rubygems.org'
+gemspec

bin/chew

@@ -0,0 +1,8 @@
+#!/usr/bin/env ruby
+
+require 'chew'
+
+Chew::setup_opts
+
+# TODO: Implement something reasonably clear
+puts "Doing things!"

bin/ltx2any

@@ -0,0 +1,6 @@
+#!/usr/bin/env ruby
+
+# TODO: remove eventually
+
+puts 'Deprecation warning: ltx2any is called chew now.'
+`chew #{ARGV.join(' ')}`

chew.gemspec

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+lib = File.expand_path('../lib', __FILE__)
+$LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
+require 'constants'
+
+Gem::Specification.new do |s|
+  s.name        = 'chew'
+  s.version     = VERSION
+  s.date        = Time.now.strftime('%Y-%m-%d')
+  s.summary     = 'Yet another LaTeX build wrapper, with one or two nifty features'
+  s.description = s.summary
+  s.authors     = ['Raphael Reitzig']
+  s.email       = '[email protected]'
+  s.homepage    = 'http://github.com/reitzig/chew'
+  s.license     = 'MIT'
+  s.required_ruby_version = '>= 2.3.0'
+
+  s.executables = ['chew', 'ltx2any']
+  s.files       = Dir['lib/**/*.rb', 'bin/*', 'LICENSE', '*.md']
+
+  #s.add_development_dependency 'github-markup', '~> 2.0'
+  #s.add_development_dependency 'json-schema', '~> 2.8'
+  #s.add_development_dependency 'minitest', '~> 5.10'
+  #s.add_development_dependency 'rake', '~> 12.3'
+  #s.add_development_dependency 'redcarpet', '~> 3.4'
+  #s.add_development_dependency 'simplecov', '~> 0.16'
+  #s.add_development_dependency 'yard', '~> 0.9'
+
+  s.add_runtime_dependency 'json', '~> 2.1'
+  s.add_runtime_dependency 'listen', '~> 3.1'
+  s.add_runtime_dependency 'parallel', '~> 1.12'
+  s.add_runtime_dependency 'ruby-progressbar', '~> 1.8'
+  s.add_runtime_dependency 'tex_log_parser', '~> 1'
+
+  #s.metadata['yard.run'] = 'yri' # use "yard" to build full HTML docs.
+end